Discovery of a new class of bicyclic substituted hydroxyphenylmethanones as 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2) inhibitors for the treatment of osteoporosis

Article abstract of DOI:10.1016/j.ejmech.2011.09.004

E2 deficiency in elderly people has directly an effect on the skeleton and can lead to osteoporosis. As 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2) catalyses the conversion between active 17β-hydroxysteroid estradiol (E2) and testosterone (T) into their less active 17-ketosteroid and has been found in bones, 17β-HSD2 inhibitor may provide a new approach in the onset of osteoporosis. Bicyclic substituted hydroxyphenylmethanone derivatives were synthesised as steroidomimetics of the substrate E2 and were evaluated for their 17β-HSD2 inhibition and their selectivity toward 17β-HSD1, catalysing the reverse reaction the conversion of estrone (E1) into E2. Highly selective compounds (11, 12, 14, 21 and 22) have been identified, the most promising one (12) showing an IC₅₀ value in the low nanomolar range (101 nM) and a selectivity factor of 13 toward 17β-HSD1. These results make compound 12 an interesting candidate for further biological evaluation.

Full text of DOI:10.1016/j.ejmech.2011.09.004

European Journal of Medicinal Chemistry 47 (2012) 1e17
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Discovery of a new class of bicyclic substituted hydroxyphenylmethanones
as 17 -hydroxysteroid dehydrogenase type 2 (17 -HSD2) inhibitors for the
treatment of osteoporosis
b
b
Marie Wetzela, Emanuele M. Garganoa, Stefan Hinsbergerb, Sandrine Marchais-Oberwinklera,
,b,
Rolf W. Hartmanna
*
a Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C23, D-66123 Saarbrücken, Germany
b Helmholtz Institute for Pharmaceutical Sciences Saarland (HIPS), Campus C23, D-66123 Saarbrücken, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
E2 deficiency in elderly people has directly an effect on the skeleton and can lead to osteoporosis. As 17
b
b
-
-
Received 11 May 2011
Received in revised form
31 August 2011
Accepted 2 September 2011
Available online 8 September 2011
hydroxysteroid dehydrogenase type
2 (17b-HSD2) catalyses the conversion between active 17
hydroxysteroid estradiol (E2) and testosterone (T) into their less active 17-ketosteroid and has been
found in bones, 17 -HSD2 inhibitor may provide a new approach in the onset of osteoporosis. Bicyclic
substituted hydroxyphenylmethanone derivatives were synthesised as steroidomimetics of the substrate
E2 and were evaluated for their 17 -HSD2 inhibition and their selectivity toward 17 -HSD1, catalysing
b
b
b
the reverse reaction the conversion of estrone (E1) into E2. Highly selective compounds (11, 12, 14, 21 and
22) have been identified, the most promising one (12) showing an IC50 value in the low nanomolar range
Keywords:
17b-HSD2
Osteoporosis
Non steroidal inhibitors
Steroidomimetics
(101 nM) and a selectivity factor of 13 toward 17
b
-HSD1. These results make compound 12 an interesting
candidate for further biological evaluation.
Ó 2011 Elsevier Masson SAS. All rights reserved.
1. Introduction
menopausal women and elderly men, after the level of active sex
steroids 17 -estradiol (hereafter “estradiol” or E2) or testosterone
b
Healthy bones are continuously regenerated by a mechanism of
balance between osteoblasts (OBs) and osteoclasts (OCs), which are
responsible for bone formation and bone resorption, respectively.
The abnormal increase of the activity of OCs compared to the one of
OBs in elderly people leads to osteoporosis [1]. Osteoporosis is
a silent and systemic skeletal disease, characterised by reduced
bone mineral density and increased risk of fractures often at the
hips, spine and wrist. Bone loss often takes place in post-
(T) (Chart 1) has dropped down.
Several drugs can be administered for the treatment of osteo-
porosis. Among the antiresorptive agents, the bisphosphonate
alendronate [2] is the most potent one used, but reduces the risk of
hip fractures only by 50% in post-menopausal women [2,3] and
elderly men [4]. Raloxifene [5], a selective estrogen receptor
modulator (SERM) is also often used to treat osteoporosis, but leads
to various adverse effects as increased risk of thromboembolism
[6], hot flushes or leg cramps. Denosumab [7], an inhibitor of the
receptor activator of nuclear factor kB ligand (RANKL) [8] inhibits
the osteoclastogenesis (OC differentiation) by binding to RANKL. It
has proven its efficacy [7,9] in post-menopausal women and elderly
men with high risk of fractures but is associated with high
cholesterol levels, muscle pain and bladder infection. Among all
current marketed osteoporosis drugs, none of them offers
a complete cure, there is therefore a need to develop new drugs for
this disease with higher efficiency.
Estrogens [10] and androgens [10] play a key role in the devel-
opment of the disease. It has been show that administration of E2
can help in the treatment of osteoporosis, but has adverse effects.
Mechanism by which estrogens act on bones is not well understood
yet, but one theory points out the importance of RANKL and
Abbreviations: 17
-hydroxysteroid dehydrogenase type 2; A-dione, 4-androstene-3,17-dione;
BMD, bone mineral density; E1, estrone; E2, 17 -estradiol; EDG, electron donating
group; equiv, equivalent; ER, estrogen receptor; EWG, electron withdrawing group;
HPLC, high pressure liquid chromatography; KO, knockout; NAD(H), nicotinamide
adenine dinucleotide; OB, osteoblast; OC, osteoclast; OPG, osteoprotegerin; RBA,
relative binding affinity; RANK(L), receptor activator of nuclear factor kB (ligand);
SAReactivity relationship, structure; SERM, selective estrogen receptor modulator;
SF, selectivity factor; T, testosterone.
b-HSD1, 17b-hydroxysteroid dehydrogenase type 1; 17b-HSD2,
17
b
b
* Corresponding author. Pharmaceutical and Medicinal Chemistry, Saarland
University, Campus C23, D-66123 Saarbrücken, Germany. Tel.: þ49 681 302 70300;
fax: þ49 681 302 70308.
E-mail address: rwh@mx.uni-saarland.de (R.W. Hartmann).
URL: http://www.pharmmedchem.de
0223-5234/$ e see front matter Ó 2011 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2011.09.004

2
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
Fig. 1. Superimposition of compound 2 (green) and E2 (blue); (A) carbonyl group of 2
mimicks the C17(OH) of E2 and the OH of the phenyl A ring the C3(OH) of the steroid;
(B) carbonyl group of 2 mimicks the C3(OH) of E2 and the OH of the phenyl A ring the
C17(OH) of the steroid. (For interpretation of the references to color in this figure
legend, the reader is referred to the web version of this article.)
osteoprotegerin (OPG) [11]. The production of OPG is stimulated by
E2 in the OBs. Binding of OPG to RANKL inhibits the activation of the
RANK receptor on osteoclasts, limiting the resorptive activity of
OCs. OPG and RANKL knockout (KO) mice confirm the possible
involvement of OPG and RANKL in bone regulation, as OPG KO mice
[12,13] exhibit severe osteoporosis due to an increase of osteo-
clastogenesis, while RANKL KO mice [14] show serious osteopet-
rosis and a complete lack of OCs. A drug which could increase the
concentration of estrogens in bones, would raise OPG levels, and
thus might diminish bone resorption and should have favorable
effects on osteoporosis.
Chart 2. Inhibitors of 17b-HSD2.
recovers the balance between bone formation and bone resorption.
A strong variability is observed, certainly due to non appropriate
pharmacokinetic properties of this compound. New 17b-HSD2
inhibitors with good pharmacokinetic properties should be iden-
tified for further in vivo experiments.
In the frame of our 17
yphenylketothiophene B (Chart 2) was identified [32] as moderate
17
-HSD2 inhibitor (IC50 ¼ 382 nM). The scaffold of B can therefore
be considered as an interesting starting point for development of
a new class of 17 -HSD2 inhibitors. Optimisation of HSD2 activity
b-HSD1 project, the hydrox-
17b-Hydroxysteroid dehydrogenase type 2 (17b-HSD2) is an
b
enzyme converting the highly active E2 and T into their less active
form, estrone (E1) and 4-androstene-3,17-dione (A-dione),
respectively, using NADþ as cofactor (Chart 1). It is mainly localised
in placenta, liver, small intestine and can be found in osteoblastic
b
and gain in selectivity toward HSD1 might be obtained by (1)
exchange of the thiophene ring by bioisosteres, (2) exchange of the
methyl substituent on the A ring, and (3) introduction of substit-
uents on the B moiety. Convenience of these compounds is the easy
four steps synthesis and purification, contrary to the pyrrolidinone
A, which requires a separation of stereoisomers.
cells [15]. Inhibitors of 17b-HSD2 could therefore maintain a high
level of E2 and T in bones, and protect them against bone loss.
Considering that systemic and intracellular modulation of hormone
concentrations has already been successfully applied for the
treatment of breast and prostate cancer and begnign prostatic
hyperplasia by inhibition of the steroidogenic enzymes aromatase
In this paper, we will report on the synthesis and the biological
evaluation of a novel class of 17b-HSD2 inhibitors, with a bicyclic
[16e18], CYP17 [19e22] and 5
e as in case of 17 -HSD1 [26e34] e is considered beneficial for
endometriosis therapy, inhibition of 17 -HSD2 could be a new
approach for the treatment of osteoporosis.
Few inhibitors of 17 -HSD2 have been identified until now
a-reductase [23e25], respectively, or
substituted hydroxyphenylmethanone core structure.
b
b
2. Results
b
2.1. Chemistry
[35e40]. Among them, the pyrrolidinone A [38] (Chart 2) is the
most potent one described in the literature (IC50 ¼ 10 nM). Efficacy
of a derivative of A has been evaluated in vivo in an osteoporotic
The synthesis of compounds 1e24 was achieved in a four step
procedure and is depicted in Scheme 1. First, the nucleophilic
addition of Grignard reagent (phenylmagnesiumbromide deriva-
tives) to the appropriate aromatic carbaldehyde (Method A) affor-
ded the alcohol intermediates 1c, 2c, 9ce12c, 14c and 22ce24c.
Then the OH-group was further oxidized into the corresponding
ketone with 2-iodoxybenzoic acid (Method B). Subsequent Suzuki
cross couplings [42] with different substituted phenylboronic acids
led to compounds 1ae24a (Method C or D). Ether cleavage [43] was
performed using boron tribromide for compounds 1, 2, 10, 11, 14e19
and 21, (method E), boron trifluoride dimethylsulfide complex for
compounds 3, 5, 6, 13 and 23 (method F) or pyridinium hydro-
chloride for compounds 4, 7e9, 12, 20, 22 and 24 (method G).
monkey model [41]. This study proved that inhibition of 17
b
-HSD2
OH
O
17β-HSD2, NAD+
17β-HSD1, NADPH
HO
HO
E2
E1
O
OH
17β-HSD2, NAD+
2.2. Biological results
17β-HSD3, NADPH
O
O
T
A-dione
2.2.1. Inhibition of human 17
17 -HSD1 and estrogen receptors (ERs)
17 -HSD2 and 17 -HSD1 inhibitory activities of the synthesised
compounds were evaluated. As 17 -HSD1 catalyses the reduction
b-HSD2 and selectivity toward
b
Chart 1. Interconversion of 17
HSD1 and of testosterone (T) to androstenedione (A-dione) by 17
HSD3.
b
-estradiol (E2) to estrone (E1) by 17
b
-HSD2 and 17
b
-
-
b
b
b-HSD2 and 17
b
b

M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
3
MgBr
R1
OH
O
O
(het-)
R2
(het-)
arom
(het-)
arom
arom
Br
Br
Br
a
H
b
R1
R1
R2
R2
1c, 2c, 9c-12c, 14c, 22c-24c
1b, 2b, 9b-12b, 14b, 22b-24b
c or d
O
O
(het-)
arom
(het-)
arom
R3
R3
e, f or g
R4
R4
R1
R2
R1
1-24
R2
1a-24a
Scheme 1. Synthesis of compounds 1e24. Reagents and conditions: a. anhydrous THF, 80 ꢀC, 3 h, Method A; b. 2-iodoxybenzoic acid, anhydrous THF, 60 ꢀC, overnight, Method B; c.
Na2CO3, Pd(PPh3)4, RB(OH)2, DME/water (2:1), microwave irradiation (25 min, 150W, 150 ꢀC, 15 bar), for compounds 15ae17a, Method C; d. Cs2CO3, Pd(PPh3)4, RB(OH)2, DME/water
(2:1), 80 ꢀC, overnight, for compounds 1ae14a, 18ae24a, Method D; e. BBr3, CH2Cl2, ꢁ78 ꢀC to rt, overnight, for compounds 1, 2, 10, 11, 14e19 and 21, Method E; f. BF3$SMe2, CH2Cl2,
rt, overnight, for compounds 3, 5, 6, 13 and 23, Method F; g. pyridinium hydrochloride, 180 ꢀC, 2 h, for compounds 4, 7e9, 12, 20, 22 and 24, Method G.
of E1 to E2, it should not be affected by 17
Moreover, inhibitors of 17 -HSD2 should have no affinity for the
estrogen receptors (ER) and , as most E2 effects are ER mediated.
b
-HSD2 inhibitors.
at 1 mM, respectively). Advantageously compound 5 with a chlorine
should be less susceptible to metabolic oxidation compared to the
CH3 compound 2. Shifting the chlorine to the ortho position (4) led
b
a
b
Human placental enzymes were used for both assays and were
to a small loss in activity (80% and 92% 17b-HSD2 inhibition at 1 mM
obtained according to described methods [44e46]. Briefly, in the
for 4: 2-Cl and 5: 3-Cl, respectively). As the exchange of the methyl
group of 2 did not improve selectivity, additional substituents were
17
tritiated E2, cofactor and inhibitor. The separation of substrate and
product was accomplished by HPLC. The 17 -HSD1 assay was
b-HSD2 assay, incubations were run with microsomal fractions,
added on the phenyl moiety B. Introduction of
(compounds 6e8) leads to highly active 17 -HSD2 inhibitors (IC50
values between 24 and 34 nM), but only a small selectivity toward
17 -HSD1 (SF between 2 and 9). Better selectivity is achieved in
a fluorine
b
b
performed similarly using tritiated E1 as substrate and the cytosolic
fraction. The percent inhibition values of compounds 1e24 are
shown in Table 1, and the IC50 values determined for selected
compounds are reported in Table 2. Compounds showing less than
b
presence of the methyl group on the A ring (6, SF ¼ 9) compared to
the chlorinated analog 7 (SF ¼ 2). Exchanging the m-OH group in
the B ring by fluorine led to a completely inactive compound (11%
10% inhibition tested at a concentration of 1
be inactive. The spiro- -lactone described by Poirier et al. [36] was
taken as external reference (65% at 1 M in our test; 62e66% at
M in their test).
In a previous work [32], focusing on the development of 17
HSD1 inhibitors, compound B has been identified as an interesting
scaffold for 17 -HSD2 inhibition with an IC50 value of 382 nM. The
goal of this study was to increase the 17 -HSD2 inhibitory activity
mM were considered to
d
inhibition at 1
been identified in the class of 1,4-disubstituted benzenes, but none
of them is highly selective toward 17 -HSD1 (compounds 2e8).
In a previous study [28], oxazole C and isoxazole D (Chart 2)
were identified as inhibitors of 17
mM for 9). New potent 17b-HSD2 inhibitors have
m
1
m
b
b
-
b
-HSD2 (IC50 ¼ 249 nM for C and
b
270 nM for D), indicating that polar moieties like O and N are well
tolerated in the central core of this class of inhibitor. With the
hypothesis that these two classes of compounds bind in the same
area of HSD2 and trying to increase the selectivity of this new class
b
and reverse selectivity in favor of HSD2. The thiophene ring of
B was first exchanged by the bioisostere benzene with 1,3- and 1,4-
substitution pattern to afford compounds 1 and 2, respectively.
of 17b-HSD2 inhibitors, a nitrogen was introduced in the 1,4-
1 turned out to be a moderate 17
b
-HSD2 inhibitor (IC50 ¼ 379 nM),
disubstituted central benzene ring leading to 3,6-pyridine 10, 2,5-
pyridine 11 and 2,6-pyridine 14. These compounds turned out to be
while the 1,4-substituted compound 2 is a very active compound
(IC50 ¼ 132 nM). Compound 2 also shows a slight selectivity toward
very active (84%, 73% and 84% 17
11 and 14, respectively). In addition, the selectivity of 11 and 14
toward 17 -HSD1 was much increased compared to the 1,4- and
b-HSD2 inhibition at 1 mM for 10,
17b-HSD1 (SF: 3). Thus, exchange of the thiophene ring by a 1,4-
substituted benzene reverses the selectivity of the starting
compound B toward 17 -HSD2. These results encouraged us
b
b
1,3-disubstituted benzenes (SF ¼ 21 and 75 for 11 and 14, respec-
tively, to be compared with SF ¼ 3 and 1 for 2 and 1, respectively). In
the 2,5-pyridine class, activity of 11 can be increased by addition of
to extend this SAR study on bicyclic substituted hydrox-
yphenylmethanones by changing the methyl group on the A ring
(compounds 3-5) and by adding further substituents on the B ring
fluorine to the
B phenyl moiety (compounds 12 and 13,
(compounds 6e9) to improve their activity for 17
b
-HSD2.
IC50 ¼ 101 nM and 153 nM respectively), but selectivity toward 17
b-
Replacement of the electron donating methyl group (EDG) of 2
by an electron withdrawing group (EWG) like a fluoro (3) is not well
tolerated by the enzyme, as compound 3 showed only 68% inhibi-
HSD1 dropped down in case of compound 13.
2,6-Substituted pyridine 14, the most selective compound of the
pyridine class was further modified trying to increase its activity.
Shifting the CH3-group from the meta- to the ortho-position of the
tion at 1
isosteric chlorine (5) led to a similar affinity to the enzyme and
a similar selectivity factor toward 17 -HSD1 (90% vs. 92% inhibition
mM. Exchange of the lipophilic methyl group (2) by a bio-
phenyl is detrimental for the activity (18% and 84% 17
b-HSD2
b
inhibition at 1 M for 18: 2-CH3 and 14: 3-CH3, respectively).
m

4
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
Table 1
Inhibition of human 17b-HSD2 and 17b-HSD1 by compounds 1e24.
O
2
O
(het-)
arom
F
F
3
R2
A
B
4
HO
B
A
R1
OH
3
HO
4
B, 1-8, 10-24
9
Compd
(Het-) arom
R1
R2
Position of
Inhibition of 17
b
-HSD2a
Inhibition of 17b
-HSD1b
the OH group in A ring
[%] at 1
m
M
[%] at 1
mM
Spiro-
B
d
-lactone
e
e
e
e
69
n.i.
H
H
3-CH3
3-CH3
4
4
75
77
94
50
S
1
2
3
H
H
3-CH3
3-F
4
4
90
68
58
26
4
5
6
7
8
9
H
H
4-F
4-F
3-F
e
2-Cl
3-Cl
3-CH3
3-Cl
3-CH3
e
4
4
4
4
4
80
92
98
100
100
11
43
66
79
95
84
16
10
11
H
H
3-CH3
3-CH3
4
4
84
73
58
24
N
N
12
13
4-F
4-F
3-CH3
3-Cl
4
4
84
87
47
50
14
H
3-CH3
4
84
n.i.
15
16
17
18
19
20
21
22
23
24
H
H
2
3
4
4
4
4
4
4
4
4
n.i.
n.i.
16
18
56
40
55
62
28
57
n.i.
n.i.
n.i.
n.i.
64
H
H
H
H
H
H
4-F
4-CH3
3-F
H
H
2-CH3
2-F
3-F
3-Cl
3-CH3
3-CH3
3-CH3
47
N
n.i.
n.i.
n.i.
n.i.
n.i.: no inhibition (inhibition < 10%).
a
Human placental, microsomal fraction, substrate [3H]-E2 þ E2 [500 nM], NADþ [1.5 mM], mean value of three determinations, relative standard deviation < 10%.
b
Human placental, cytosolic fraction, substrate [3H]-E1 þ E1 [500 nM], NADH [0.5 mM], mean value of three determinations, relative standard deviation < 10%.
Exchange of the methyl by an EWG like fluorine (19: 2-F and 20:
3-F) or chlorine (21: 3-Cl) led to a regain of activity (56%, 40% and
55% 17 -HSD2 inhibition at M, respectively), but these
compounds are not able to reach the activity of compound 14 (84%
inhibition at 1 M). Furthermore, addition of an EWG (compounds
paraemeta OH substitution pattern of 14 is the best one for a high
17 -HSD2 inhibitory activity. Compounds 15e17 as well as their
analogs with methoxy groups (data not shown) turned out to be
only weak HSD2 inhibitors. It can be concluded that the methyl
group next to the OH in the A ring plays an important role for the
b
b
1
m
m
22 and 24) or an EDG (compound 23) group in the 3-hydroxyphenyl
B moiety is detrimental for the activity, as the compounds show
a weaker inhibition compared to the parent compound 14 (62%,
inhibition of 17
Eleven compounds were identified as highly active 17
inhibitors with IC50 values below 300 nM, with three of them
selective toward 17 -HSD1 (SF > 10). The most potent compounds
have been evaluated for their binding affinities to the ER and
expressed as relative binding affinity (RBA). The RBA represents the
ligand affinity to ER, relative to the one of E2, which is arbitrarily set
up at 100%. The tested compounds showed very low affinities to
both ER subtypes (<0.1%).
b-HSD2 and should not be omitted.
b
-HSD2
28% and 58% 17
dently of the position of the fluorine (62% and 57% 17
inhibition at 1 M for 22: 4-F and 24: 5-F, respectively).
b
-HSD2 inhibition at 1
m
M, respectively), indepen-
b
b
-HSD2
a
b,
m
As none of the substituted 2,6-pyridines reached the activity of
14, the position of the OH group on the A ring has been studied in
absence of the 3-methyl group to investigate whether the

M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
5
Table 2
(IC50 ¼ 18 nM, SF ¼ 5), while compound 15 is inactive. Comparison
of these results indicates that the 2,5-thiophene and the 2,6-
pyridine derivatives do not bind in the same way in the enzyme
active site. Furthermore, the inactivity of 17 shows that the methyl
group on the A ring plays a key role for the binding of the
compound in the enzyme. The methyl group might be located in
a small lipophilic pocket and might form Van der Waals interac-
tions. In the 1,4-benzene class (compounds 2, 5, 6 and 7) and 2,5-
pyridine class (compounds 12 and 13), the methyl could be
replaced by a chlorine without loss of activity, confirming that the
amino acids around this region of the enzyme should be lipophilic.
Interestingly, the nitrogen of the pyridine seems to be respon-
IC50 values, selectivity factor for selected compounds.
Compd
Cell-free assay
Selectivity factorc
a
17
b
-HSD2 IC50 [nM]
17
b
-HSD1 IC50b [nM]
8
B
1
2
3
4
5
6
7
382
379
132
525
176
153
34
0.02
1
3
5
11
4
9
2
5
3
21
13
7
75
81
30
475
413
2429
1764
571
289
24
31
53
8
159
567
10
11
12
13
14
21
22
220
260
101
153
263
752
757
sible for the high selectivity observed toward 17
effect of the nitrogen on selectivity was already identified in the
frame of our 17 -HSD1 inhibitors development: polar atoms are not
tolerated in the active site of 17 -HSD1 [28] while they are
advantageous in 17 -HSD2 (compounds C and D) [28,47]. The
b-HSD1. A similar
5482
1272
1013
19646
60638
22395
b
b
b
position of the nitrogen on the central core also plays a key role for
the selectivity. Compound 10, with the nitrogen next to the A ring is
an unselective 17b-HSD2 inhibitor, while compound 11 with the
nitrogen next to the B ring is a highly selective inhibitor.
In the optimisation process of the 2,5-pyridine class, activity of
11 can be increased by introduction of a fluorine into the B ring,
thereby leading to the identification of the highly active and
a
Human placental, microsomal fraction, substrate [3H]-E2
þ
E2 [500 nM],
cofactor NADþ [1.5 mM], mean value of three determinations, relative standard
deviation < 10%.
b
Human placental, cytosolic fraction, substrate [3H]-E1 þ E1 [500 nM], cofactor
NADH [0.5 mM], mean value of three determinations, relative standard
deviation < 10%.
c
IC50 (17b-HSD1)/IC50 (17b-HSD2).
selective compound 12 as most promising 17b-HSD2 inhibitor in
this study. This compound as well as the most interesting mole-
3. Discussion and conclusion
cules identified (2, 5, 6, 7, 8, 11 and 14) show a negligible affinity to
both receptors ER
In this paper, we described the synthesis and the biological eval-
uationofa newclass of 17 -HSD2 inhibitors, derivedfromsubstituted
bicyclic hydroxyphenylmethanones. The influence of different six-
membered rings as central core and different small substituents on
the phenyl moieties A and B were investigated. Structural optimisa-
a and b.
In this study, starting from compound B [32] as moderate 17b-
HSD2 inhibitor, we have developed a new class of active and
selective 17 -HSD2 inhibitors. Exchange of the thiophene moiety of
B by a six-membered ring (benzene or pyridine) with different
substitution patterns inverses the selectivity of B in favor of 17
HSD2 and leads to highly potent 17 -HSD2 inhibitors.
b
b
b
-
b
tion of the starting compound B led to new highly potent 17b-HSD2
The best inhibitory activity was obtained when the core struc-
ture is a 1,4-substituted benzene (compound 2). Changing the
substitution pattern to 1,3-substituted benzene leads to a loss in
activity, indicating that the linear geometry of the inhibitors suits
better to the enzyme binding pocket. Furthermore, the compounds
are believed to be steroidomimetics as the 1,4-substituted benzene
derivatives superimpose well with the substrate E2 (Fig.1): because
of the pseudosymmetry the inhibitors can overlay with E2 in two
ways: either the carbonyl group of 2 mimicks the C17(OH) of E2 and
the OH of the phenyl A ring the C3(OH) of the steroid (Fig. 1A) or
vice versa (Fig. 1B).
inhibitors (compounds 6, 7, 8, 12 and 13) with inhibitory activities in
the low nanomolar range. Selectivity was achieved by introduction of
a nitrogen inthe centralcore, while activity wasincreased byaddition
of a fluorine in the B ring. Thereby, compound 12 was identified as the
most promising derivative of this series with activity in the low
nanomolar range, a striking selectivity toward 17b-HSD1 and no
affinity on both ERs. This inhibitor seems to be the best candidate for
being further evaluated for its pharmacokinetic profile and for its
in vivo activity in a disease-oriented model to validate the concept of
17b-HSD2 inhibition.
Introduction of a fluorine on the B ring in compounds bearing
the 1,4- substitution pattern results in highly potent inhibitors
(compounds 6e8, 12 and 13). This fluorine might interact with
amino acids of the active site via H-bond interaction, which could
stabilise the binding of the inhibitor. Interestingly, the position of
the fluorine is not important for activity, as compounds 6 and 8
4. Experimental section
4.1. Chemical methods
1H NMR and 13C NMR spectra were recorded on a Bruker DRX-
500 instrument in CDCl3 or acetone-d6. Chemicals shifts are re-
show similar HSD2 inhibition. As the 3D-structure of 17
unknown, it is not possible to discuss the binding interactions of
the compounds with the enzyme in more detail.
b
-HSD2 is
ported in d values (ppm), the hydrogenated residues of deuterated
solvent were used as internal standard (CDCl3:
d
¼ 7.26 ppm in 1H
NMR and
NMR and
d
¼ 77 ppm in 13C NMR, acetone-d6:
d
¼ 2.05 ppm in 1
H
Regarding the pyridine derivatives (compounds 10, 11 and 14),
the introduction of a nitrogen in the phenyl ring decreases inhibi-
tory activity. None of these compounds is as active as the corre-
sponding 1,4-benzene derivative. With the aim to increase activity
in the pyridine class, the best hydroxyphenyl substitution pattern
was investigated in the class of the 2,6-pyridines (compounds
15e17) in absence of the methyl group. These compounds showed
either very low activity (17) or were inactive (15 and 16). A similar
compound to 15 with the OH group in ortho-position of the A ring
was described by Oster et al. [32], with a 2,5-thiophene as central
d
¼ 30.8 ppm and 206.3 ppm in 13C NMR). Signals are
described as s, br, d, t, dd, ddd, dt and m for singlet, broad, doublet,
triplet, doublet of doublets, doublet of doublet of doublets, doublet
of triplets and multiplet, respectively. All coupling constants (J) are
given in Hertz.
Tested compounds are ꢂ95% chemical purity as measured by
HPLC. The SurveyorÒ-LC-system consisted of a pump, an auto-
sampler, and a PDA detector. Mass spectrometry was performed on
a TSQÒ Quantum (ThermoFisher, Dreieich, Germany). The triple
quadrupole mass spectrometer was equipped with an electrospray
interface (ESI) and atmospheric pressure chemical ionisation
core. This compound is a highly potent 17b-HSD2 inhibitor

6
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
(APCI), respectively. The system was operated by the standard
software XcaliburÒ. A RP C18 NUCLEODURÒ 100-5 (3 mm) column
(Macherey-Nagel GmbH, Dühren, Germany) was used as stationary
phase. All solvents were HPLC grade. In a gradient run the
percentage of acetonitrile (containing 0.1% trifluoroacetic acid) in
0.1% trifluoroacetic acid in was increased from an initial concen-
tration of 5% at 0 min to 100% at 15 min and kept at 100% for 5 min.
palladium (0.02 equiv) was suspended in a degazed DME/water
(2:1) solution. The reaction mixture was exposed to microwave
irradiation (25 min, 150 W, 150 ꢀC, 15 bar). After reaching room
temperature, water was added to quench the reaction and the
aqueous layer was extracted with ethyl acetate. The combined
organic layers were washed with brine, dried over sodium sulfate,
filtered and concentrated to dryness. The product was purified by
column chromatography.
The injection volume was 20 mL and flow rate was set to 800 mL/
min. MS analysis was carried out at a needle voltage of 3000 V and
a capillary temperature of 350 ꢀC. Mass spectra were acquired in
positive mode and in negative mode when required from 100 to
1000 m/z and UV spectra were recorded at the wavelength of
254 nm and in some cases at 360 nm.
4.4.2. Method D
A mixture of arylbromide (1 equiv), boronic acid (1.2 equiv),
cesium carbonate (4 equiv), and tetrakis(triphenylphosphine)
palladium (0.02 equiv) was suspended in a DME/water (2:1) solu-
tion and the mixture was degazed. The mixture was heated to 80 ꢀC
and stirred overnight at 80 ꢀC under nitrogen. The reaction mixture
was cooled to room temperature, quenched by water and extracted
with ethyl acetate. The organic layer was washed with brine, dried
over sodium sulfate, filtered and concentrated to dryness. The
product was purified by column chromatography or by
recrystallisation.
GC/MS spectra were measured on a GCD Series G1800A (Hew-
lett Packard) instrument with an Optima-5-MS (0.25
column (Macherey-Nagel).
mM, 30 m)
All microwave irradiation experiments were carried out in
a CEM-Discover microwave apparatus.
Melting points were measured on a Stuart Scientific SMP3
apparatus.
Flash chromatography was performed on silica gel 40 (35/
40e63/70 mM) with hexane/ethyl acetate mixtures as eluents, and
4.5. General procedures for ether cleavage
the reaction progress was determined by thin-layer chromatog-
raphy analyses on Alugram SIL G/UV254 (Macherey-Nagel). Visu-
alization was accomplished with UV light. Purification by
preparative TLC was performed on 1 mm SIL G-100 UV254 glass
plates (Macherey-Nagel). Purification with preparative HPLC were
carried out on a Agilent 1200 series HPLC system from Agilent
4.5.1. Method E
To a solution of methoxy derivative (1 equiv) in dry dichloro-
methane cooled at ꢁ78 ꢀC under nitrogen was slowly added boron
tribromide (1 M solution in dichloromethane, 5 equiv per methoxy
function). The reaction mixture was stirred at ꢁ78 ꢀC for 1 h and
then allowed to warm to room temperature overnight. The reaction
was quenched by water and extracted with ethyl acetate. The
combined organic layers were washed with brine and dried over
sodium sulfate, filtered, evaporated to dryness under reduced
pressure and purified by column chromatography.
Technologies, using
a
RP C18 Nucleodur 100-5 column
(30$100 mm/50 m e from Macherey-Nagel GmbH) as stationary
m
phase with acetonitrile/water or isopropanol/water as solvent in
a gradient from 20:80 to 100:0 in 40 min.
Starting materials were used as obtained from Aldrich, Acros,
Alfa Aeser and Combi-blocks without further purification. No
attempts were made to optimise yields.
4.5.2. Method F
To a solution of methoxy derivative (1 equiv) in dry dichloro-
methane, boron trifluoride dimethylsulfide complex (35 equiv per
methoxy function) was added dropwise at room temperature. The
reaction mixture was stirred at room temperature overnight. Water
was added to quench the reaction and the aqueous layer was
extracted with ethyl acetate. The combined organic layers were
washed with brine, dried over sodium sulfate, filtered, evaporated
to dryness under reduced pressure and purified by column
chromatography.
4.2. General procedure for alcohol formation
4.2.1. Method A
To a mixture of aldehyde (1 equiv) in dry THF was added the
magnesiumbromide derivative (2.2 equiv) under nitrogen. The
reaction mixture was heated to 80 ꢀC and stirred for 3 h at 80 ꢀC.
The reaction mixture was cooled to room temperature, quenched
with brine and the aqueous layer was extracted with ethyl acetate.
The combined organic layers were dried over sodium sulfate,
filtered and concentrated to dryness. The product was purified by
column chromatography.
4.5.3. Method G
To pyridinium hydrochloride (100 equiv) at 190 ꢀC was added
the methoxy derivative (1 equiv). The reaction mixture was
stirred for 2 h, cooled to room temperature and then stirred with
1N HCl for 1 h. The mixture was extracted in ethyl acetate. The
combined organic layers were washed with water, dried over
sodium sulfate, filtered, evaporated to dryness under reduced
pressure and purified by column chromatography or by
recrystallisation.
4.3. General procedure for oxidation of alcohol in ketone
4.3.1. Method B
To a mixture of alcohol (1 equiv) in dry THF was added
2-iodoxybenzoic acid (2 equiv). The reaction mixture was stirred at
60 ꢀC overnight, cooled to room temperature and quenched with
Na2S2O3. The aqueous layer was extracted with ethyl acetate and
the organic layer was washed with water, neutralised with 0.5N
NaOH and dried over sodium sulfate, filtered and concentrated to
dryness. The product was purified by column chromatography or
by recrystallisation.
4.6. Detailed synthesis procedure
4.6.1. (3-Bromophenyl)-(3-methoxyphenyl)-methanol (1c)
The title compound was prepared by reaction of 3-bromophenyl
4.4. General procedures for Suzuki coupling
carboxaldehyde (500 mg, 2.71 mmol,
3-methoxyphenylmagnesiumbromide (1
1
equiv) with
M
in THF) (1.35 g,
4.4.1. Method C
5.95 mL, 5.95 mmol, 2.2 equiv) according to method A. The product
was used in the next step without further purification. C14H13BrO2;
MW 293.
A mixture of arylbromide (1 equiv), boronic acid (1.2 equiv),
sodium carbonate (2 equiv), and tetrakis(triphenylphosphine)

M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
7
4.6.2. (3-Bromophenyl)-(3-methoxyphenyl)-methanone (1b)
of the analytically pure compound as a colorless oil. C14H11BrO2;
MW 290; 1H NMR (acetone-d6):
7.73e7.70 (m, 4H), 7.46e7.42 (m,
1H), 7.32e7.29 (m, 2H), 7.21 (ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz,
1H), 3.85 (s, 3H); 13C NMR (acetone-d6):
195.3, 160.7, 139.5, 137.5,
132.5, 130.4, 127.7, 123.1, 119.5, 115.2, 55.9; IR: 3003, 2834, 1651,
1575, 1234 cmꢁ1
Thetitle compoundwasprepared byreactionof(3-bromophenyl)-
(3-methoxyphenyl)-methanol 1c (460 mg, 1.57 mmol, 1 equiv) with
2-iodoxybenzoic acid (885 mg, 3.14 mmol, 2 equiv) according to
method B. The product was purified by column chromatography
(hexane/ethyl acetate 9:1) to give 200 mg (44%) of the analytically
pure compound as a yellow oil. C14H11BrO2; MW 291; 1H NMR
d
d
.
(acetone-d6):
d
7.92e7.90 (m, 1H), 7.82 (ddd, J ¼ 0.9 Hz, J ¼ 1.9 Hz,
4.6.7. (40-Methoxy-30-methylbiphenyl-4-yl)-(3-methoxyphenyl)-
methanone (2a)
Thetitlecompoundwaspreparedbyreactionof(4-bromophenyl)-
(3-methoxyphenyl)-methanone 2b (410 mg,1.41 mmol,1 equiv) with
4-methoxy-3-methylphenylboronic acid (281 mg, 1.69 mmol, 1.2
equiv) according to method D. The product was used in the next step
without further purification. C22H20O3; MW 332.
J ¼ 7.9 Hz,1H), 7.76e7.73 (m,1H), 7.50 (t, J ¼ 8.2 Hz,1H), 7.48e7.44 (m,
1H), 7.34e7.30 (m, 2H), 7.23 (ddd, J ¼ 1.3 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz,1H),
3.86 (s, 3H); 13C NMR (acetone-d6):
d 195.8, 161.7, 141.6, 140.1, 136.9,
134.0, 132.2, 131.4, 130.4, 124.1, 123.9, 120.6, 116.2, 56.8.
4.6.3. (40-Methoxy-30-methylbiphenyl-3-yl)-(3-methoxyphenyl)-
methanone (1a)
Thetitlecompoundwaspreparedbyreactionof(3-bromophenyl)-
(3-methoxyphenyl)-methanone 1b (200 mg, 0.69 mmol, 1 equiv)
with 4-methoxy-3-methylphenylboronic acid (137 mg, 0.82 mmol,
1.2equiv)according tomethod D.Theproductwaspurifiedbycolumn
chromatography (hexane/ethyl acetate 95:5) to afford 200 mg (88%)
of the analytically pure compound as a yellow oil. C22H20O3; MW 332;
4.6.8. (40-Hydroxy-30-methylbiphenyl-4-yl)-(3-hydroxyphenyl)-
methanone (2)
The title compound was prepared by reaction of (40-methoxy-30-
methylbiphenyl-4-yl)-(3-methoxyphenyl)-methanone 2a (460 mg,
1.38 mmol, 1 equiv) with boron tribromide (13.8 mmol, 10 equiv)
according to method E. The product was purified by column chro-
matography (hexane/ethyl acetate 8:2) then by preparative TLC
(hexane/ethyl acetate 7:3 þ 10 drops of HCOOH) to afford 120 mg
(29%) of the analytically pure compound as an orange solid.
1H NMR (acetone-d6):
d 8.00e7.98 (m, 1H), 7.90e7.87 (m, 1H),
7.71e7.68 (m,1H), 7.59 (t, J ¼ 7.9 Hz,1H), 7.52e7.45 (m, 3H), 7.38e7.35
(m, 2H), 7.25e7.21 (m,1H), 7.02 (d, J ¼ 9.1 Hz,1H), 3.87 (s, 6H), 2.25 (s,
3H); 13C NMR (acetone-d6):
d
196.3, 160.7, 158.8, 142.0, 140.0, 139.2,
C20H16O3; MW 304; 1H NMR (acetone-d6):
d 8.68 (s, br, 1H), 8.46 (s,
134.8, 132.0, 131.2, 130.4, 130.0, 129.7, 128.7, 128.4, 127.6, 126.4, 123.2,
119.3, 115.2, 111.4, 55.9, 55.8, 16.4.
br,1H), 7.85e7.82 (m, 2H), 7.77e7.74 (m, 2H), 7.54 (d, J ¼ 2.2 Hz,1H),
7.44 (dd, J ¼ 1.9 Hz, J ¼ 7.9 Hz, 1H), 7.37 (t, J ¼ 7.9 Hz, 1H), 7.29e7.24
(m, 2H), 7.13 (ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 6.96 (d,
4.6.4. (40-Hydroxy-30-methylbiphenyl-3-yl)-(3-hydroxyphenyl)-
methanone (1)
J ¼ 8.2 Hz, 1H), 2.30 (s, 3H); 13C NMR (acetone-d6):
d 196.9, 159.3,
157.9, 146.9, 141.3, 137.3, 132.7, 132.3, 131.5, 131.3, 127.8, 127.5, 126.8,
122.9,121.2,118.0,117.1,17.3; IR: 3363,1641,1588,1449 cmꢁ1; LC/MS
m/z: 305 (M þ H)þ.
The title compound was prepared by reaction of (40-methoxy-30-
methylbiphenyl-3-yl)-(3-methoxyphenyl)-methanone 1a (200 mg,
0.60 mmol, 1 equiv) with boron tribromide (6 mmol, 10 equiv)
according to method E. The product was purified by column chro-
matography (hexane/ethyl acetate 8:2) then by preparative TLC
(hexane/ethyl acetate 7:3) to afford 44 mg (24%) of the analytically
pure compound as a yellow oil. C20H16O3; MW 304; 1H NMR
4.6.9. (30-Fluoro-40-methoxybiphenyl-4-yl)-(3-methoxyphenyl)-
methanone (3a)
Thetitlecompoundwaspreparedbyreactionof(4-bromophenyl)-
(3-methoxyphenyl)-methanone 2b (200 mg, 0.69 mmol, 1 equiv)
with 3-fluoro-4-methoxyphenylboronic acid (141 mg, 0.81 mmol,1.2
equiv) according to method D. The product was used in the next step
without further purification. C21H17FO3; MW 336.
(acetone-d6):
d 8.72 (s, br, 1H), 8.38 (s, br, 1H), 7.97e7.95 (m, 1H),
7.86e7.83 (m, 1H), 7.67e7.65 (m, 1H), 7.57 (t, J ¼ 7.6 Hz, 1H), 7.46 (d,
J ¼ 2.2 Hz, 1H), 7.40e7.35 (m, 2H), 7.33e7.31 (m, 1H), 7.30e7.28 (m,
1H), 7.14 (dd, J ¼ 2.5 Hz, J ¼ 7.9 Hz,1H), 6.94 (d, J ¼ 8.2 Hz,1H), 2.28 (s,
3H); 13C NMR (acetone-d6):
d
197.3, 159.1, 157.3, 143.0, 140.8, 140.1,
4.6.10. (30-Fluoro-40-hydroxybiphenyl-4-yl)-(3-hydroxyphenyl)-
methanone (3)
132.9, 131.8, 131.2, 131.1, 130.4, 129.3, 129.0, 127.1, 126.6, 122.9, 121.3,
117.9, 116.9, 17.1; IR: 3320, 1641, 1581, 1476, 1358, 1220 cmꢁ1; LC/MS
m/z: 305 (M þ H)þ.
The title compound was prepared by reaction of (30-fluoro-40-
methoxy-biphenyl-4-yl)-(3-methoxyphenyl)-methanone 3a (20 mg,
0.06 mmol, 1 equiv) with boron trifluoride dimethylsulfide complex
(4.2 mmol, 70 equiv)according tomethod F. The product waspurified
by column chromatography (hexane/ethyl acetate 1:1). Yield: 8 mg
4.6.5. (4-Bromophenyl)-(3-methoxyphenyl)-methanol (2c)
The title compound was prepared by reaction of 4-bromophenyl
carboxaldehyde (1 g, 5.41 mmol, 1 equiv) with 3-methoxyphen-
ylmagnesiumbromide (1 M in THF) (2.70 g, 11.9 mmol, 11.9 mL, 2.2
equiv) according to method A. The product was purified by column
chromatography (hexane/ethyl acetate 9:1) to afford 1.58 g (100%) of
(43%). C19H13FO3; MW 308; 1H NMR (acetone-d6):
d 8.88 (s, br, 1H),
8.68 (s, br,1H), 7.87e7.80 (m, 4H), 7.55 (dd, J ¼ 2.3 Hz, J ¼ 12.2 Hz,1H),
7.47 (ddd, J ¼ 0.9 Hz, J ¼ 2.1 Hz, J ¼ 8.4 Hz, 1H), 7.39 (t, J ¼ 7.8 Hz,1H),
7.28e7.25 (m, 2H), 7.16e7.12 (m, 2H); 13C NMR (acetone-d6):
d 195.9,
the analytically pure compound as a colorless oil. C14H13BrO2; MW
144.5, 140.1, 137.0, 131.3, 130.4, 127.0, 124.2, 121.9, 120.3, 116.9, 115.5,
1
292; H NMR (acetone-d6):
d
7.50e7.47 (m, 2H), 7.41e7.38 (m, 2H),
115.4; IR: 3333, 2981, 1637, 1305 cmꢁ1; GC/MS m/z: 308 (M)þ.
7.23(t, J¼ 7.9Hz,1H), 7.06e7.04(m,1H), 7.00e6.97(m,1H), 6.81(ddd,
J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 5.81 (d, J ¼ 4.0 Hz, 1H), 5.01 (d,
4.6.11. (20-Chloro-40-methoxybiphenyl-4-yl)-(3-methoxyphenyl)-
methanone (4a)
J¼ 4.0Hz,1H), 3.76 (s, 3H); 13CNMR(acetone-d6):
d160.8,147.5,145.7,
132.0, 130.2, 129.4, 121.2, 119.6, 113.3, 113.1, 75.5, 55.5.
The title compound was prepared by reaction of
(4-bromophenyl)-(3-methoxyphenyl)-methanone 2b (262 mg,
0.90 mmol, 1 equiv) with 2-chloro-4-methoxyphenylboronic acid
(201 mg, 1.08 mmol, 1.2 equiv) according to the method D. The
product was recrystallised in ethanol to afford 193 mg (61%) of the
analytically pure compound as white crystals. C21H17ClO3; MW
4.6.6. (4-Bromophenyl)-(3-methoxyphenyl)-methanone (2b)
The title compound was prepared by reaction of (4-bromo-
phenyl)-(3-methoxyphenyl)-methanol 2c (1.5 g, 5.12 mmol, 1
equiv) with 2-iodoxybenzoic acid (2.88 mg, 10.2 mmol, 2 equiv)
according to method B. The product was purified by column
chromatography (hexane/ethyl acetate 95:5) to afford 1.39 g (94%)
353; mp: 119e121 ꢀC; 1H NMR (CDCl3):
7.56e7.53 (m, 2H), 7.41e7.38 (m, 3H), 7.29 (d, J ¼ 8.5 Hz, 1H),
d 7.88e7.85 (m, 2H),

8
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
7.17e7.13 (m, 1H), 7.05 (d, J ¼ 2.5 Hz, 1H), 6.91 (dd, J ¼ 2.8 Hz,
and concentrated to dryness under vacuum. The product was
used in the next step without further purification. C14H12BrFO2;
MW 311.
J ¼ 8.8 Hz, 1H), 3.89 (s, 3H), 3.86 (s, 3H); 13C NMR (CDCl3):
d 196.1,
159.8, 143.4, 139.0, 136.3, 133.9, 131.9, 131.8, 129.9, 129.5, 129.2,
122.8, 118.8, 115.4, 114.3, 113.3, 55.6, 55.5; IR: 2954, 1647, 1597,
1034 cmꢁ1; GC/MS m/z: 352 (M)þ.
4.6.16. (4-Bromophenyl)-(4-fluoro-3-methoxyphenyl)-methanone
(6b)
4.6.12. (20-Chloro-40-hydroxybiphenyl-4-yl)-(3-hydroxyphenyl)-
methanone (4)
The title compound was prepared by reaction of
(4-bromophenyl)-(4-fluoro-3-methoxyphenyl)-methanol 6c (468mg,
1.50 mmol,1 equiv) with 2-iodoxybenzoic acid (3.00 mmol, 2 equiv)
according to method B. The product was purified by column chro-
matography (hexane/ethyl acetate 7:3) to afford 280 mg (60%) of the
analytically pure compound. C14H10BrFO2; MW 309; 1H NMR
The title compound was prepared by reaction of (20-chloro-40-
methoxybiphenyl-4-yl)-(3-methoxyphenyl)-methanone 4a (100 mg,
0.28 mmol, 1 equiv) with pyridinium hydrochloride (28 mmol, 100
equiv) according to method G. The product was purified by
recrystallisation in hexane to afford 67 mg (74%) of the analyti-
cally pure compound as a brown solid. C19H13ClO3; MW 325; mp:
(acetone-d6):
d
7.77e7.72 (m, 4H), 7.56 (dd, J ¼ 1.9 Hz, J ¼ 8.5 Hz,1H),
7.39e7.36 (m, 1H), 7.33e7.28 (m, 1H), 3.96 (s, 3H); 13C NMR
212e214 ꢀC; 1H NMR (acetone-d6):
d
8.67 (s, br, 1H), 7.87e7.83 (m,
(acetone-d6): d 194.3, 137.5, 134.8, 132.5, 132.4, 127.6, 124.6, 118.6,
2H), 7.61e7.58 (m, 2H), 7.42e7.37 (m, 1H), 7.33 (d, J ¼ 8.2 Hz, 1H),
7.31e7.29 (m, 1H), 7.27 (ddd, J ¼ 0.9 Hz, J ¼ 1.6 Hz, J ¼ 7.6 Hz, 1H),
7.14 (ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 7.05 (d, J ¼ 2.5 Hz,
1H), 6.95 (dd, J ¼ 2.5 Hz, J ¼ 8.5 Hz, 1H); 13C NMR (acetone-d6):
117.8, 116.6, 116.5, 115.5, 56.7; GC/MS m/z: 308e310 (M)þ.
4.6.17. (4-Fluoro-3-methoxyphenyl)-(40-methoxy-30-
methylbiphenyl-4-yl)-methanone (6a)
d
159.0, 158.3, 144.3, 140.0, 137.3, 133.1, 131.5, 130.4, 122.0, 120.4,
The titlecompound was prepared by reaction of (4-bromophenyl)-
(4-fluoro-3-methoxyphenyl)-methanone 6b (142 mg, 0.46 mmol, 1
equiv) with 4-methoxy-3-methylphenylboronic acid (92 mg,
0.55 mmol, 1.2 equiv) according to method D. The product was
recrystallised in ethanol to afford 98 mg (61%) of the analytically pure
compound as a white solid. C22H19FO3; MW 350; mp: 145e146 ꢀC; 1H
117.6, 117.0, 115.7; IR: 3292, 1645, 1589, 1451 cmꢁ1; LC/MS m/z:
325 (M þ H)þ.
4.6.13. (30-Chloro-40-hydroxybiphenyl-4-yl)-(3-methoxyphenyl)-
methanone (5a)
The title compound was prepared by reaction of
(4-bromophenyl)-(3-methoxyphenyl)-methanone 2b (200 mg,
0.69 mmol, 1 equiv) with 3-chloro-4-hydroxyphenylboronic acid
(143 mg, 0.83 mmol, 1.2 equiv) according to method D. The product
was purified by column chromatography (hexane/ethyl acetate 7:3)
to afford 120 mg (51%) of the analytically pure compound.
NMR (acetone-d6): d 7.87e7.84 (m, 2H), 7.81e7.78 (m, 2H), 7.60e7.56
(m, 3H), 7.40 (ddd, J ¼ 1.9 Hz, J ¼ 4.4 Hz, J ¼ 8.2 Hz, 1H), 7.30 (dd,
J ¼ 8.2 Hz, J ¼ 11.0 Hz, 1H), 7.05 (d, J ¼ 8.2 Hz,1H), 3.97 (s, 3H), 3.90 (s,
3H), 2.27 (s, 3H); 13C NMR (acetone-d6):
d 194.7, 159.2, 148.8, 148.7,
145.7, 136.3, 138.6, 135.6, 132.3, 131.3, 130.1, 127.7, 127.0, 126.6, 124.4,
124.3, 116.5, 115.5, 111.4, 56.7, 55.8, 16.4; IR: 2922, 1645, 1601,
1027 cmꢁ1; GC/MS m/z: 350 (M)þ.
C20H15ClO3; MW 338; 1H NMR (acetone-d6):
d 9.03 (s, br, 1H),
7.86e7.83 (m, 2H), 7.80e7.77 (m, 2H), 7.74 (d, J ¼ 2.2 Hz, 1H), 7.57
(dd, J ¼ 2.2 Hz, J ¼ 8.5 Hz, 1H), 7.47e7.41 (m, 1H), 7.33e7.30 (m, 2H),
7.20 (ddd, J ¼ 0.9 Hz, J ¼ 2.7 Hz, J ¼ 8.2 Hz, 1H), 7.14e7.11 (m, 1H),
4.6.18. (4-Fluoro-3-hydroxyphenyl)-(40-hydroxy-30-
methylbiphenyl-4-yl)-methanone (6)
3.85 (s, 3H); 13C NMR (acetone-d6):
d
194.9, 159.8, 153.3, 143.4,
The title compound was prepared by reaction of (4-fluoro-3-
methoxyphenyl)-(40-methoxy-30-methylbiphenyl-4-yl)-meth-
anone 6a (98 mg, 0.30 mmol, 1 equiv) with pyridinium hydro-
chloride (30 mmol, 100 equiv) according to method G. The product
was recrystallised in hexane to afford 40 mg (41%) of the analyti-
cally pure compound as a green powder. C20H15FO3; MW 322; mp:
139.2, 136.0, 132.4, 130.5, 130.0, 129.4, 128.5, 126.9, 126.8, 126.2,
122.1, 121.0, 118.2, 117.3, 114.3, 54.9.
4.6.14. (30-Chloro-40-hydroxybiphenyl-4-yl)-(3-hydroxyphenyl)-
methanone (5)
The title compound was prepared by reaction of (30-chloro-40-
hydroxybiphenyl-4-yl)-(3-methoxyphenyl)-methanone 5a (60 mg,
203e205 ꢀC; 1H NMR (acetone-d6):
d 9.04 (s, br, 1H), 8.47 (s, br, 1H),
7.84e7.76 (m, 4H), 7.54 (d, J ¼ 1.8 Hz, 1H), 7.48 (dd, J ¼ 2.0 Hz,
J ¼ 8.6 Hz, 1H), 7.46 (dd, J ¼ 2.2 Hz, J ¼ 8.2 Hz, 1H), 7.34e7.28 (m,
2H), 6.96 (d, J ¼ 8.3 Hz, 1H), 2.29 (s, 3H); 13C NMR (acetone-d6):
0.18 mmol,
1 equiv) with boron trifluoride dimethylsulfide
complex (6.2 mmol, 35 equiv) according to method F. The product
was purified by column chromatography (hexane/ethyl acetate
1:1). Yield: 40 mg (69%). C19H13ClO3; MW 324; 1H NMR (acetone-
d
194.7, 156.9, 156.0, 154.0, 145.9, 145.7, 136.2, 135.7, 131.7, 131.2,
130.5, 126.8, 126.5, 125.9, 123.3, 123.2, 120.1, 116.8, 116.1, 16.3; IR:
d6):
d
9.00 (s, br, 1H), 8.67 (s, br, 1H), 7.84e7.81 (m, 2H), 7.79e7.75
3307, 1642, 1592, 1429 cmꢁ1; LC/MS m/z: 323 (M þ H)þ.
(m, 2H), 7.73 (d, J ¼ 2.2 Hz, 1H), 7.56 (dd, J ¼ 2.2 Hz, J ¼ 8.4 Hz, 1H),
7.35 (t, J ¼ 7.9 Hz, 1H), 7.25e7.21 (m, 2H), 7.12 (d, J ¼ 8.5 Hz, 1H),
7.09 (ddd, J ¼ 1.1 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H); 13C NMR (acetone-
4.6.19. (30-Chloro-40-hydroxybiphenyl-4-yl)-(4-fluoro-3-
methoxyphenyl)-methanone (7a)
The title compound was prepared by reaction of (4-bromophenyl)-
(4-fluoro-3-methoxyphenyl)-methanone 6b (127 mg, 0.41 mmol,
d6):
d
195.9, 158.3, 154.2, 144.2, 140.2, 137.1, 133.3, 131.4, 130.4,
129.3, 127.7, 127.1, 121.9, 121.8, 120.3, 118.2, 117.0; GC/MS m/z:
324e326 (M)þ.
1
equiv) with 3-chloro-4-hydroxyphenylboronic acid (85 mg,
0.49 mmol,1.2 equiv) according to method D. The product was used in
4.6.15. (4-Bromophenyl)-(4-fluoro-3-methoxyphenyl)-methanol (6c)
To a solution of 5-bromo-2-fluoroanisole (547 mg, 2.67 mmol,
1 equiv) in anhydrous THF was added granules of magnesium
(68 mg, 2.80 mmol, 1.05 equiv) under nitrogen. The mixture was
heated to 60 ꢀC for 2 h. After cooling to room temperature,
4-bromobenzaldehyde (592 mg, 3.20 mmol, 1.2 equiv) was added
and the reaction mixture was stirred at 80 ꢀC overnight. The
reaction was cooled to room temperature, quenched with brine
and the aqueous layer was extracted with ethyl acetate. The
combined organic layers were dried over sodium sulfate, filtered
the next step without further purification. C20H14ClFO3; MW 357.
4.6.20. (30-Chloro-40-hydroxybiphenyl-4-yl)-(4-fluoro-3-
hydroxyphenyl)-methanone (7)
The title compound was prepared by reaction of (30-chloro-40-
hydroxybiphenyl-4-yl)-(4-fluoro-3-methoxyphenyl)-methanone
7a (126 mg, 0.35 mmol, 1 equiv) with pyridinium hydrochloride
(35 mmol, 100 equiv) according to method G. The product was
purified by column chromatography (hexane/ethyl acetate 7:3)
then by preparative HPLC (isopropanol/water) to afford 38 mg

M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
9
(32%) of the analytically pure compound as a yellow solid.
C19H12ClFO3; MW 343; 1H NMR (acetone-d6):
9.04 (s, br, 1H), 9.02
overnight. The reaction was cooled to room temperature, quenched
with brine and the aqueous layer was extracted with ethyl acetate.
The combined organic layers were dried over sodium sulfate,
filtered and concentrated to dryness under vacuum. The product
was used in the next step without further purification. C13H9BrF2O;
MW 299.
d
(s, br, 1H), 7.86e7.83 (m, 2H), 7.82e7.80 (m, 2H), 7.76 (d, J ¼ 2.2 Hz,
1H), 7.60 (dd, J ¼ 2.2 Hz, J ¼ 8.5 Hz, 1H), 7.48 (dd, J ¼ 1.9 Hz,
J ¼ 8.5 Hz, 1H), 7.34e7.31 (m, 1H), 7.31e7.26 (m, 1H), 7.16 (d,
J ¼ 8.5 Hz, 1H); 13C NMR (acetone-d6):
d 193.8, 153.3, 143.3, 136.1,
134.6, 132.4, 130.4, 128.4, 127.5, 126.2, 122.4, 121.0, 119.2, 118.5,
118.4, 117.3, 117.0, 116.0, 115.8; IR: 3320, 1650, 1593, 1058 cmꢁ1; LC/
MS m/z: 344e346 (M þ H)þ.
4.6.26. (4-Bromophenyl)-(3,4-difluorophenyl)-methanone (9b)
Thetitlecompoundwaspreparedbyreactionof(4-bromophenyl)-
(3,4-difluorophenyl)-methanol 9c (589 mg, 1.97 mmol, 1 equiv) with
2-iodoxybenzoic acid (1.38 g, 4.93 mmol, 2.5 equiv) according to
method B. The product was purified by recrystallisation in ethanol to
afford 140 mg (24%) of the analytically pure compound as a white
powder. C13H7BrF2O; MW 297; mp: 74e77 ꢀC; 1H NMR (acetone-d6):
4.6.21. (4-Bromophenyl)-(3-fluoro-5-methoxyphenyl)-methanol
(8c)
To a solution of 3-bromo-5-fluoroanisole (500 mg, 2.44 mmol, 1
equiv) in anhydrous THF was added granules of magnesium (64 mg,
2.56 mmol, 1.05 equiv) under nitrogen. The mixture was heated
d
7.79e7.74 (m, 5H), 7.70e7.66 (m, 1H), 7.56e7.50 (m, 1H); 13C NMR
to 60 ꢀC for
2
h. After reaching room temperature,
(acetone-d6): d 193.3, 151.9, 151.8, 136.9, 135.5, 132.7, 132.4, 128.3,
4-bromobenzaldehyde (542 mg, 2.93 mmol, 1.2 equiv) was added
and the reaction mixture was stirred at 80 ꢀC overnight. The reac-
tion was cooled to room temperature, quenched with brine and the
aqueous layer was extracted with ethyl acetate. The combined
organic layers were dried over sodium sulfate, filtered and
concentrated to dryness under vacuum. The product was used in
the next step without further purification. C14H12BrFO2; MW 311.
128.2,128.0,119.8,119.6,118.6; IR: 1650,1604,1280 cmꢁ1; GC/MSm/z:
296e298 (M)þ.
4.6.27. (3,4-Difluorophenyl)-(40-methoxy-30-methylbiphenyl-4-yl)-
methanone (9a)
The title compound was prepared by reaction of
(4-bromophenyl)-(3,4-difluorophenyl)-methanone 9b (168 mg,
0.52 mmol, 1 equiv) with 4-methoxy-3-methylphenylboronic acid
(103 mg, 0.62 mmol, 1.2 equiv) according to method D. The
compound was recrystallised in ethanol to obtain 157 mg of the
analytically pure product as a white powder. C21H16F2O2; MW 338;
4.6.22. (4-Bromophenyl)-(3-fluoro-5-methoxyphenyl)-methanone
(8b)
The title compound was prepared by reaction of
(4-bromophenyl)-(3-fluoro-5-methoxyphenyl)-methanol 8c (306 mg,
0.98 mmol,1 equiv) with 2-iodoxybenzoic acid (553 mg,1.96 mmol,
2 equiv) according to method B. The product was used in the next
step without further purification. C14H10BrFO2; MW 309.
mp: 123e125 ꢀC; 1H NMR (acetone-d6):
d 7.88e7.84 (m, 2H),
7.82e7.79 (m, 2H), 7.75 (ddd, J ¼ 2.2 Hz, J ¼ 7.9 Hz, J ¼ 11.0 Hz, 1H),
7.71e7.67 (m, 1H), 7.61e7.57 (m, 2H), 7.56e7.50 (m, 1H), 7.06 (d,
J ¼ 8.2 Hz, 1H), 3.90 (s, 3H), 2.27 (s, 3H); 13C NMR (acetone-d6):
d
193.6, 159.3, 146.1, 135.7, 131.4, 130.1, 128.1, 128.0, 127.8, 127.2,
4.6.23. (3-Fluoro-5-methoxyphenyl)-(40-methoxy-30-methylbiphenyl-
4-yl)-methanone (8a)
126.7, 119.7, 119.5, 111.4, 55.9, 16.4; IR: 2930, 1645, 1596, 1141 cmꢁ1
;
GC/MS m/z: 338 (M)þ.
Thetitlecompoundwaspreparedbyreactionof(4-bromophenyl)-
(3-fluoro-5-methoxyphenyl)-methanone 8b (175 mg, 0.57 mmol, 1
equiv) with 4-methoxy-3-methylphenylboronic acid (113 mg,
0.68 mmol,1.2 equiv) accordingto method D. The product wasused in
the next step without further purification. C22H19FO3; MW 350.
4.6.28. (3,4-Difluorophenyl)-(4-hydroxy-30-methylbiphenyl-4-yl)-
methanone (9)
The title compound was prepared by reaction of (3,4-
difluorophenyl)-(40-methoxy-3-methylbiphenyl-4-yl)-methanone
9a (100 mg, 0.30 mmol, 1 equiv) with pyridinium hydrochloride
(30 mmol, 100 equiv) according to method G. The product was
purified by recrystallisation in hexane to afford 35 mg (36%) of the
analytically pure compound as a yellow solid. C20H14F2O2; MW 324;
4.6.24. (3-Fluoro-5-hydroxyphenyl)-(40-hydroxy-30-methylbiphenyl-
4-yl)-methanone (8)
The title compound was prepared by reaction of (3-fluoro-
5-methoxyphenyl)-(40-methoxy-30-methylbiphenyl-4-yl)-meth-
anone 8a (100 mg, 0.29 mmol, 1 equiv) with pyridinium
hydrochloride (29.0 mmol, 100 equiv) according to method G.
The product was purified by preparative HPLC (gradient water/
mp: 174e176 ꢀC; 1H NMR (acetone-d6):
d 8.54 (s, br, 1H), 7.86e7.83
(m, 2H), 7.80e7.77 (m, 2H), 7.77e7.74 (m, 1H), 7.71e7.67 (m, 1H),
7.56e7.50 (m, 2H), 7.45 (ddd, J ¼ 0.6 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H),
6.96 (d, J ¼ 8.2 Hz, 1H), 2.29 (s, 3H); 13C NMR (acetone-d6):
d 193.7,
isopropanol) to afford
5
mg (5%) of the analytically pure
9.17
157.1, 152.7, 152.6, 151.8, 149.9, 146.4, 135.5, 131.4, 130.5, 127.0, 126.5,
compound. C20H15FO3; MW 322; 1H NMR (acetone-d6):
d
119.7,119.5,118.4,118.3,116.2,16.3; IR: 3427,1645,1594,1287 cmꢁ1
;
(s, br, 1H), 8.48 (s, br, 1H), 7.87e7.84 (m, 2H), 7.80e7.77 (m, 2H),
7.56e7.54 (m, 1H), 7.45 (ddd, J ¼ 0.6 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz,
1H), 7.10e7.08 (m, 1H), 6.99 (ddd, J ¼ 1.3 Hz, J ¼ 2.5 Hz,
J ¼ 8.8 Hz, 1H), 6.96 (d, J ¼ 8.5 Hz, 1H), 6.87 (dt, J ¼ 2.2 Hz,
GC/MS m/z: 324 (M)þ.
4.6.29. (6-Bromopyridin-3-yl)-(3-methoxyphenyl)-methanol (10c)
The title compound was prepared by reaction of
6-bromopyridin-3-yl carboxaldehyde (500 mg, 2.69 mmol, 1 equiv)
with 3-methoxyphenylmagnesiumbromide (1 M in THF) (1.35 g,
5.91 mmol, 2.2 equiv) according to method A. The product was
purified by column chromatography (hexane/ethyl acetate 7:3) to
afford 700 mg (89%) of the analytically pure compound as a color-
J ¼ 10.4 Hz, 1H), 2.29 (s, 3H); 13C NMR (acetone-d6):
d 195.7,
160.9, 158.0, 147.3, 142.7, 142.6, 136.7, 132.6, 132.3, 131.5, 127.9,
127.5, 126.9, 117.1, 114.6, 109.1, 108.2, 108.0, 17.3; LC/MS m/z:
323 (M þ H)þ.
4.6.25. (4-Bromophenyl)-(3,4-difluorophenyl)-methanol (9c)
less oil. C13H12BrNO2; MW 294; 1H NMR (acetone-d6):
d 8.45e8.43
To a solution of 1-bromo-3,4-difluorobenzene (1.00 g, 0.59 mL,
5.18 mmol, 1 equiv) in anhydrous THF was added granules of
magnesium (132 mg, 5.44 mmol, 1.05 equiv) under nitrogen. The
mixture was heated to 60 ꢀC for 2 h. After cooling to room
temperature, 4-bromobenzaldehyde (592 mg, 3.20 mmol, 1.2
equiv) was added and the reaction mixture was stirred at 80 ꢀC
(m, 1H), 7.71 (ddd, J ¼ 0.6 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 7.52 (d,
J ¼ 8.8 Hz, 1H), 7.25 (t, J ¼ 8.2 Hz, 1H), 7.06e7.04 (m, 1H), 7.00e6.97
(m, 1H), 6.82 (ddd, J ¼ 0.9 Hz, J ¼ 2.8 Hz, J ¼ 8.2 Hz, 1H), 5.89 (d,
J ¼ 4.1 Hz, 1H), 5.21 (d, J ¼ 4.1 Hz, 1H), 3.77 (s, 3H); 13C NMR
(acetone-d6):
d 161.8, 150.4, 147.6, 142.4, 142.0, 139.0, 131.3, 129.5,
120.3, 114.6, 113.8, 74.3, 56.5.

10
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
4.6.30. (6-Bromopyridin-3-yl)-(3-methoxyphenyl)-methanone
(10b)
4.6.34. (5-Bromopyridin-2-yl)-(3-methoxyphenyl)-methanone
(11b)
The title compound was prepared by reaction of (6-
bromopyridin-3-yl)-(3-methoxyphenyl)-methanol 10c (700 mg,
2.38 mmol, 1 equiv) with 2-iodoxybenzoic acid (1.34 g, 4.76 mmol,
2 equiv) according to method B. The product was purified by
column chromatography (hexane/ethyl acetate 9:1) to give 520 mg
(75%) of the analytically pure compound as a colorless oil.
The title compound was prepared by reaction of
(5-bromopyridin-2-yl)-(3-methoxyphenyl)-methanol 11c (490 mg,
1.67 mmol,1 equiv) with 2-iodoxybenzoic acid (940 mg, 3.33 mmol,
2 equiv) according to method B. The product was purified by
column chromatography (hexane/ethyl acetate 9:1) to afford
365 mg (75%) of the analytically pure compound as a colorless oil.
C13H10BrNO2; MW 292; 1H NMR (acetone-d6):
d
8.70 (d, J ¼ 1.8 Hz,
C13H10BrNO2; MW 292; 1H NMR (acetone-d6):
d
8.80 (dd, J ¼ 0.6 Hz,
1H), 8.07 (dd, J ¼ 2.4 Hz, J ¼ 8.2 Hz, 1H), 7.80 (dd, J ¼ 0.6 Hz,
J ¼ 8.2 Hz, 1H), 7.51e7.47 (m, 1H), 7.38e7.35 (m, 2H), 7.26 (ddd,
J ¼ 0.9 Hz, J ¼ 2.7 Hz, J ¼ 8.2 Hz,1H), 3.87 (s, 3H); 13C NMR (acetone-
J ¼ 2.2 Hz, 1H), 8.25 (dd, J ¼ 2.2 Hz, J ¼ 8.2 Hz, 1H), 7.97 (dd,
J ¼ 0.6 Hz, J ¼ 8.2 Hz, 1H), 7.65e7.61 (m, 2H), 7.45e7.41 (m, 1H), 7.21
(ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 3.86 (s, 3H); 13C NMR
d6):
d
161.8, 152.9, 147.2, 141.5, 139.8, 134.6, 131.6, 129.9, 124.2, 121.2,
(acetone-d6): d 193.7, 161.3, 155.6, 151.3, 141.9, 139.3, 131.0, 127.7,
116.0, 56.9.
125.7, 125.3, 120.7, 117.3, 56.8.
4.6.31. [6-(4-Methoxy-3-methylphenyl)-pyridin-3-yl]-(3-
methoxyphenyl)-methanone (10a)
4.6.35. [5-(4-Methoxy-3-methylphenyl)-pyridin-2-yl]-(3-
methoxyphenyl)-methanone (11a)
The title compound was prepared by reaction of
(6-bromopyridin-3-yl)-(3-methoxyphenyl)-methanone 10b (520 mg,
1.80 mmol, 1 equiv) with 4-methoxy-3-methylphenylboronic acid
(359 mg, 2.16 mmol, 1.2 equiv) according to method D. The product
was purified by column chromatography (hexane/ethyl acetate 9:1)
to afford 536 mg (89%) of the analytically pure compound as
The title compound was prepared by reaction of
(5-bromopyridin-2-yl)-(3-methoxyphenyl)-methanone 11b (365
mg, 1.25 mmol, 1 equiv) with 4-methoxy-3-methylphenylboronic
acid (249 mg, 1.50 mmol, 1.2 equiv) according to method D. The
product was purified by column chromatography (hexane/ethyl
acetate 9:1) to give 362 mg (87%) of the analytically pure compound
a yellow oil. C21H19NO3; MW 333; 1H NMR (acetone-d6):
d
8.74 (dd,
as yellow solid. C21H19NO3; MW 333; 1H NMR (acetone-d6):
d 8.95
J ¼ 0.9 Hz, J ¼ 2.2 Hz, 1H), 7.91 (dd, J ¼ 2.2 Hz, J ¼ 8.2 Hz, 1H),
7.83e7.80 (m, 2H), 7.74 (dd, J ¼ 0.6 Hz, J ¼ 8.5 Hz, 1H), 7.28e7.24 (m,
1H), 7.17e7.14 (m, 2H), 7.02 (ddd, J ¼ 1.3 Hz, J ¼ 2.5 Hz, J ¼ 8.5 Hz,
1H), 6.81 (d, J ¼ 9.1 Hz,1H), 3.68 (s, 3H), 3.66 (s, 3H), 2.05 (s, 3H); 13C
(dd, J ¼ 0.6 Hz, J ¼ 2.2 Hz,1H), 8.18 (dd, J ¼ 2.5 Hz, J ¼ 8.2 Hz,1H), 8.06
(dd, J ¼ 0.6 Hz, J ¼ 8.2 Hz, 1H), 7.75e7.71 (m, 2H), 7.62e7.59 (m, 2H),
7.45e7.41 (m,1H), 7.20 (ddd, J ¼ 0.9 Hz, J ¼ 2.8 Hz, J ¼ 8.2 Hz,1H), 7.06
(dd, J ¼ 2.2 Hz, J ¼ 7.3 Hz,1H), 3.89 (s, 3H), 3.87 (s, 3H), 2.27 (s, 3H); 13C
NMR (acetone-d6):
d
195.5, 161.7, 161.5, 152.6, 140.6, 139.7, 131.9,
NMR (acetone-d6): d 194.1, 161.3, 160.6, 154.9, 148.0, 140.3, 140.0,
131.5, 131.3, 128.4, 128.2, 124.0, 120.6, 120.3, 116.0, 112.0, 56.9,
56.8, 17.5.
136.1, 131.1, 130.8, 130.3, 129.0, 127.9, 126.2, 125.4, 120.2, 117.6, 112.6,
56.8, 56.7, 17.4.
4.6.32. [6-(4-Hydroxy-3-methylphenyl)-pyridin-3-yl]-(3-
hydroxyphenyl)-methanone (10)
4.6.36. [5-(4-Hydroxy-3-methylphenyl)-pyridin-2-yl]-(3-
hydroxyphenyl)-methanone (11)
The title compound was prepared by reaction of [6-(4-
methoxy-3-methylphenyl)-pyridin-3-yl]-(3-methoxyphenyl)-
methanone 10a (466 mg, 1.40 mmol, 1 equiv) with boron tri-
bromide (14.0 mmol, 10 equiv) according to method E. The
product was purified by column chromatography (hexane/ethyl
acetate 8:2) to give 321 mg (75%) of the analytically pure
compound as a yellow powder. C19H15NO3; MW 305; 1H NMR
The title compound was prepared by reaction of [5-(4-
methoxy-3-methylphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-
methanone 11a (362 mg, 1.09 mmol, 1 equiv) with boron tri-
bromide (10.9 mmol, 10 equiv) according to method E. The
product was purified by column chromatography (hexane/ethyl
acetate 8:3) then by preparative TLC (hexane/ethyl acetate 7:3)
to give 127 mg (45%) of the analytically pure compound as yellow
powder. C19H15NO3; MW 305; mp: 178e180 ꢀC; 1H NMR
(acetone-d6):
d
8.94 (dd, J ¼ 0.6 Hz, J ¼ 2.1 Hz, 1H), 8.73 (s, br,
2H), 8.14 (dd, J ¼ 2.1 Hz, J ¼ 8.2 Hz, 1H), 8.04 (dd, J ¼ 0.6 Hz,
J ¼ 2.1 Hz, 1H), 7.99 (dd, J ¼ 0.6 Hz, J ¼ 8.2 Hz, 1H), 7.94 (dd,
J ¼ 2.1 Hz, J ¼ 8.5 Hz, 1H), 7.44e7.39 (m, 1H), 7.32e7.29 (m, 2H),
7.17e7.14 (m, 1H), 6.97 (d, J ¼ 8.2 Hz, 1H), 2.30 (s, 3H); 13C NMR
(acetone-d6):
d
8.93 (d, J ¼ 1.8 Hz, 1H), 8.62 (s, br, 1H), 8.61 (s, br,
1H), 8.19 (dd, J ¼ 2.1 Hz, J ¼ 8.2 Hz, 1H), 8.04 (d, J ¼ 8.2 Hz, 1H),
7.63e7.58 (m, 3H), 7.50 (dd, J ¼ 1.8 Hz, J ¼ 8.2 Hz, 1H), 7.37e7.32
(m, 1H), 7.13e7.09 (m, 1H), 7.00 (d, J ¼ 8.2 Hz, 1H), 2.31 (s, 3H); 13C
(acetone-d6):
d
194.7, 160.7, 158.4, 151.5, 139.7, 138.7, 131.4,
NMR (acetone-d6): d 194.4, 158.9, 158.4, 154.9, 147.8, 140.6, 140.1,
130.9, 130.6, 130.4, 127.1, 125.6, 122.0, 120.7, 119.2, 116.9, 115.9,
16.3; IR: 3431, 1648, 1582, 1473, 1268 cmꢁ1; LC/MS m/z: 306
(M þ H)þ.
135.9, 131.6, 130.9, 129.7, 127.7, 127.3, 126.2, 124.3, 121.5, 119.2,
117.4, 17.3; IR: 3350, 1644, 1580, 1514, 1240 cmꢁ1; LC/MS m/z: 306
(M þ H)þ.
4.6.33. (5-Bromopyridin-2-yl)-(3-methoxyphenyl)-methanol (11c)
The title compound was prepared by reaction of
5-bromopyridin-2-yl carboxaldehyde (500 mg, 2.69 mmol, 1 equiv)
with 3-methoxyphenylmagnesiumbromide (1 M in THF) (1.35 g,
5.9 mL, 5.91 mmol, 2.2 equiv) according to method A. The product
was purified by column chromatography (hexane/ethyl acetate 8:2)
to give 490 mg (62%) of the analytically pure compound as a red oil.
4.6.37. (5-Bromopyridin-2-yl)-(4-fluoro-3-methoxyphenyl)-
methanol (12c)
To a solution of 5-bromo-2-fluoroanisole (1.00 g, 4.88 mmol,
1 equiv) in anhydrous THF was added granules of magnesium
(125 mg, 5.12 mmol, 1.05 equiv) under nitrogen. The mixture was
heated to 60 ꢀC for 2 h. After cooling to room temperature,
5-bromo-2-formylpyridine (1.09 g, 5.86 mmol, 1.2 equiv) was
added and the reaction mixture was stirred at 80 ꢀC overnight. The
reaction was cooled to room temperature, quenched with brine
and the aqueous layer was extracted with ethyl acetate. The
combined organic layers were dried over sodium sulfate, filtered
and concentrated to dryness under vacuum. The product was used
in the next step without further purification. C13H11BrFNO2;
MW 312.
C13H12BrNO2; MW 294; 1H NMR (acetone-d6):
d
8.57 (dd, J ¼ 0.6 Hz,
J ¼ 2.5 Hz, 1H), 7.94 (dd, J ¼ 2.5 Hz, J ¼ 8.5 Hz, 1H), 7.56e7.53 (m,
1H), 7.21 (t, J ¼ 7.9 Hz, 1H), 7.07e7.05 (m, 1H), 7.04e7.00 (m, 1H),
6.79 (ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 5.80 (d, J ¼ 4.4 Hz,
1H), 5.25 (d, J ¼ 4.4 Hz, 1H), 3.76 (s, 3H); 13C NMR (acetone-d6):
d
192.6, 164.4, 161.6, 151.0, 147.2, 141.2, 131.0, 124.0, 120.6, 114.4,
114.0, 77.3, 56.4.

M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
11
4.6.38. (5-Bromopyridin-2-yl)-(4-fluoro-3-methoxyphenyl)-
methanone (12b)
The title compound was prepared by reaction of
(5-bromopyridin-2-yl)-(4-fluoro-3-methoxyphenyl)-methanol 12c
J ¼ 2.2 Hz, J ¼ 8.5 Hz, 1H), 7.28 (dd, J ¼ 8.2 Hz, J ¼ 11.4 Hz, 1H), 7.20
(d, J ¼ 8.5 Hz, 1H), 3.97 (s, 3H); 13C NMR (acetone-d6):
d 191.6, 154.8,
154.3, 147.0, 138.2, 135.5, 130.2, 129.6, 128.0, 126.2, 126.1, 125.4,
122.2, 118.4, 116.8, 116.3, 116.1, 56.6; GC/MS m/z: 356e358 (M)þ.
(463 mg, 1.48 mmol,
1 equiv) with 2-iodoxybenzoic acid
(2.96 mmol, 2 equiv) according to method B. The product was
4.6.42. (4-Fluoro-3-hydroxyphenyl)-[5-(3-chloro-4-
purified by column chromatography (hexane) to afford 354 mg
hydroxyphenyl)-pyridin-2-yl]-methanone (13)
(77%) of the analytically pure compound as
a
yellow oil.
The title compound was prepared by reaction of (4-fluoro-3-
methoxyphenyl)-[5-(3-chloro-4-hydroxyphenyl)-pyridin-2-yl]-
methanone 13a (59 mg, 0.17 mmol, 1 equiv) with boron trifluoride
dimethylsulfide complex (5.95 mmol, 35 equiv) according to
method F. The product was purified by column chromatography
(hexane/ethyl acetate 6:4) then by preparative HPLC (isopropanol/
water) to afford 10 mg (17%) of the analytically pure product.
C13H9BrFNO2; MW 310; 1H NMR (acetone-d6):
d
6.28 (dd, J ¼ 2.2 Hz,
J ¼ 8.2 Hz, 1H), 8.06e8.03 (m, 2H), 7.99 (dd, J ¼ 0.9 Hz, J ¼ 8.5 Hz,
1H), 7.89 (dd, J ¼ 2.2 Hz, J ¼ 8.5 Hz, 1H), 7.77 (ddd, J ¼ 1.9 Hz,
J ¼ 4.4 Hz, J ¼ 8.5 Hz, 1H), 3.96 (s, 3H); 13C NMR (acetone-d6):
d
191.4, 167.6, 154.5, 150.3, 141.1, 133.8, 130.4, 129.3, 126.8, 126.2,
116.6, 116.2, 56.7; IR: 2835, 1678, 1601, 1290 cmꢁ1; LC/MS m/z:
310e312 (M þ H)þ.
C18H11ClFNO3; MW 343; 1H NMR (acetone-d6):
d 9.10 (s, br, 2H),
8.98 (d, J ¼ 2.2 Hz, 1H), 8.27 (dd, J ¼ 2.5 Hz, J ¼ 7.9 Hz, 1H),
8.09e8.06 (m, 1H), 7.87 (dd, J ¼ 2.2 Hz, J ¼ 8.8 Hz, 1H), 7.84 (d,
J ¼ 2.2 Hz, 1H), 7.73 (ddd, J ¼ 1.9 Hz, J ¼ 4.4 Hz, J ¼ 8.5 Hz, 1H), 7.66
(dd, J ¼ 2.2 Hz, J ¼ 8.5 Hz, 1H), 7.25 (dd, J ¼ 8.5 Hz, J ¼ 10.7 Hz, 1H),
4.6.39. (4-Fluoro-3-methoxyphenyl)-[5-(4-methoxy-3-
methylphenyl)-pyridin-2-yl]-methanone (12a)
The title compound was prepared by reaction of
(5-bromopyridin-2-yl)-(4-fluoro-3-methoxyphenyl)-methanone
7.20 (d, J ¼ 8.5 Hz, 1H); 13C NMR (acetone-d6):
d 191.8, 156.4, 154.8,
12b (300 mg, 0.97 mmol,
1
equiv) with 4-methoxy-3-
154.4, 147.0, 145.5, 145.4, 138.2, 135.5, 134.4, 129.6, 128.0, 125.3,
122.2, 121.4, 119.4, 118.4, 116.5; IR: 3355, 1647, 1578, 1517,
1265 cmꢁ1; LC/MS m/z: 344e346 (M þ H)þ.
methylphenylboronic acid (193 mg, 1.16 mmol, 1.2 equiv) accord-
ing to method D. The product was recrystallised in acetonitrile to
afford 279 mg (82%) of the analytically pure compound as a yellow
powder. C21H18FNO3; MW 351; mp: 141e143 ꢀC; 1H NMR (CDCl3):
4.6.43. (6-Bromopyridin-2-yl)-(3-methoxyphenyl)-methanol (14c)
The title compound was prepared by reaction of
6-bromopyridin-2-yl carboxaldehyde (1 g, 5.41 mmol,1 equiv) with
3-methoxyphenylmagnesiumbromide (1 M in THF) (2.70 g, 11.9 mL,
11.9 mmol, 2.2 equiv) according to method A. The product was
purified by column chromatography (hexane/ethyl acetate 8:2) to
afford 936 mg (59%) of the analytically pure product. C13H12BrNO2;
d
8.89 (dd, J ¼ 0.6 Hz, J ¼ 2.2 Hz, 1H), 8.09 (dd, J ¼ 0.6 Hz, J ¼ 8.2 Hz,
1H), 8.02 (dd, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 7.82 (dd, J ¼ 2.2 Hz,
J ¼ 8.5 Hz, 1H), 7.77 (ddd, J ¼ 2.2 Hz, J ¼ 4.4 Hz, J ¼ 8.5 Hz, 1H), 7.46
(dd, J ¼ 2.5 Hz, J ¼ 8.2 Hz,1H), 7.44e7.42 (m,1H), 7.15 (dd, J ¼ 8.5 Hz,
J ¼ 10.7 Hz, 1H), 6.94 (d, J ¼ 8.2 Hz, 1H), 3.95 (s, 3H), 3.88 (s, 3H),
2.30 (s, 3H); 13C NMR (CDCl3):
d 192.0, 158.9, 156.8, 153.0, 147.9,
147.8,146.7,139.2,134.7,133.3,129.7,128.8,126.1,125.8,125.2,115.9,
MW 294; 1H NMR (acetone-d6):
d
7.57 (t, J ¼ 7.6 Hz, 1H), 7.49 (d,
115.8, 110.8, 56.6, 55.7, 16.6; GC/MS m/z: 351 (M)þ.
J ¼ 7.6 Hz, 1H), 7.30 (d, J ¼ 7.9 Hz, 1H), 7.08 (t, J ¼ 8.2 Hz, 1H),
6.93e6.90 (m, 1H), 6.87 (d, J ¼ 7.6 Hz, 1H), 6.66 (dd, J ¼ 2.4 Hz,
J ¼ 8.2 Hz, 1H), 5.63 (d, J ¼ 4.5 Hz, 1H), 5.05 (d, J ¼ 4.5 Hz, 1H), 3.62
4.6.40. (4-Fluoro-3-hydroxyphenyl)-[5-(4-hydroxy-3-
methylphenyl)-pyridin-2-yl]-methanone (12)
(s, 3H); 13C NMR (acetone-d6):
d 165.5, 159.8, 145.1, 140.4, 139.7,
The title compound was prepared by reaction of (4-fluoro-3-
methoxyphenyl)-[5-(4-methoxy-3-methylphenyl)-pyridin-2-yl]-
methanone 12a (70 mg, 0.20 mmol, 1 equiv) with pyridinium
hydrochloride (20.0 mmol, 100 equiv) according to method G. The
product was purified by preparative HPLC (isopropanol/water) to
give 21 mg (33%) of the analytically pure compound as a yellow
powder. C19H14FNO3; MW 323; mp: 221e223 ꢀC; 1H NMR (acetone-
129.2, 126.4, 119.4, 118.8, 112.5, 75.5, 54.5.
4.6.44. (6-Bromopyridin-2-yl)-(3-methoxyphenyl)-methanone
(14b)
The title compound was prepared by reaction of
(6-bromopyridin-2-yl)-(3-methoxyphenyl)-methanol 14c (930 mg,
3.19 mmol,1 equiv) with 2-iodoxybenzoic acid (1.80 g, 6.39 mmol, 2
equiv) according to method B. The product was purified by column
chromatography (hexane/ethyl acetate 9:1) to afford 727 mg (78%)
of the analytically pure compound as a yellow solid. C13H10BrNO2;
d6):
d
8.94 (dd, J ¼ 0.6 Hz, J ¼ 2.2 Hz, 1H), 8.64 (s, br, 1H), 8.20 (dd,
J ¼ 2.2 Hz, J ¼ 8.2 Hz, 1H), 8.05 (dd, J ¼ 0.9 Hz, J ¼ 8.2 Hz, 1H), 7.87
(dd, J ¼ 2.2 Hz, J ¼ 8.8 Hz, 1H), 7.74 (ddd, J ¼ 2.2 Hz, J ¼ 4.4 Hz,
J ¼ 8.5 Hz, 1H), 7.60 (dd, J ¼ 0.6 Hz, J ¼ 2.2 Hz, 1H), 7.50 (ddd,
J ¼ 0.6 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 7.24 (dd, J ¼ 8.5 Hz, J ¼ 11.0 Hz,
1H), 7.00 (d, J ¼ 8.2 Hz, 1H), 2.30 (s, 3H); 13C NMR (acetone-d6):
MW 292; 1H NMR (acetone-d6):
d
8.02 (dd, J ¼ 1.6 Hz, J ¼ 7.6 Hz,
1H), 7.99 (t, J ¼ 7.3 Hz, 1H), 7.86 (dd, J ¼ 1.6 Hz, J ¼ 7.3 Hz, 1H),
7.65e7.61 (m, 2H), 7.47e7.43 (m, 1H), 7.23 (ddd, J ¼ 0.9 Hz,
J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 3.87 (s, 3H); 13C NMR (acetone-d6):
d
192.7, 158.3, 157.2, 154.6, 147.6, 140.5, 135.9, 131.5, 129.5, 127.5,
127.1, 126.1, 125.7, 125.6, 122.3, 117.3, 117.2, 117.1, 17.1; IR: 3179, 2971,
d 193.5, 160.4, 156.7, 141.2, 141.1, 138.0, 131.9, 124.4, 120.1, 119.2,
1607, 1511, 1124 cmꢁ1; LC/MS m/z: 324 (M þ H)þ.
116.3, 115.2, 55.8; IR: 1667, 1425, 1254, 1032 cmꢁ1; LC/MS m/z:
292e294 (M þ H)þ.
4.6.41. (4-Fluoro-3-methoxyphenyl)-[5-(3-chloro-4-
hydroxyphenyl)-pyridin-2-yl]-methanone (13a)
4.6.45. [6-(4-Methoxy-3-methylphenyl)-pyridin-2-yl]-(3-
methoxyphenyl)-methanone (14a)
The title compound was prepared by reaction of
(5-bromopyridin-2-yl)-(4-fluoro-3-methoxyphenyl)-methanone 12b
(150 mg, 0.48 mmol, 1 equiv) with 3-chloro-4-hydroxyphenylbor-
onic acid (100 mg, 0.58 mmol, 1.2 equiv) according to method D.
The product was recrystallised in ethyl acetate to afford 72 mg
The title compound was prepared by reaction of (6-brom-
opyridin-2-yl)-(3-methoxyphenyl)-methanone 14b (410 mg, 1.40
mmol, 1 equiv) with 4-methoxy-3-methylphenylboronic acid
(280 mg, 1.69 mmol, 1.2 equiv) according to method D. The product
was purified by column chromatography (hexane/ethyl acetate 9:1)
to give 432 mg (92%) of the analytically pure compound as a yellow
(42%) of the analytically pure product as
a yellow solid.
C19H13ClFNO3; MW 357; mp: 195e197 ꢀC; 1H NMR (acetone-d6):
d
9.20 (s, br, 1H), 9.00 (dd, J ¼ 0.6 Hz, J ¼ 2.2 Hz, 1H), 8.28 (dd,
powder. C21H19NO3; MW 333; 1H NMR (acetone-d6):
d 8.10 (dd,
J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 8.11 (dd, J ¼ 0.6 Hz, J ¼ 8.2 Hz, 1H), 7.97
(dd, J ¼ 2.2 Hz, J ¼ 8.5 Hz, 1H), 7.88e7.84 (m, 2H), 7.67 (dd,
J ¼ 0.9 Hz, J ¼ 7.9 Hz,1H), 8.07e8.03 (m,1H), 7.99e7.95 (m, 2H), 7.89
(dd, J ¼ 0.9 Hz, J ¼ 7.6 Hz, 1H), 7.80e7.78 (m, 1H), 7.75 (dt, J ¼ 0.9 Hz,

12
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
J ¼ 7.6 Hz, 1H), 7.48 (t, J ¼ 7.9 Hz, 1H), 7.24 (ddd, J ¼ 0.9 Hz,
J ¼ 2.8 Hz, J ¼ 8.2 Hz,1H), 7.02 (d, J ¼ 8.2 Hz,1H), 3.89 (s, 3H), 3.88 (s,
J ¼ 1.8 Hz, J ¼ 7.9 Hz, 1H), 7.48 (t, J ¼ 7.9 Hz, 1H), 7.40 (t, J ¼ 8.1 Hz,
1H), 7.24 (ddd, J ¼ 0.9 Hz, J ¼ 2.6 Hz, J ¼ 8.2 Hz, 1H), 7.02 (ddd,
J ¼ 0.7 Hz, J ¼ 2.6 Hz, J ¼ 8.7 Hz, 1H), 3.87 (s, 3H), 3.85 (s, 3H); 13C
3H), 2.24 (s, 3H); 13C NMR (acetone-d6):
d 193.6, 160.4, 160.1, 156.5,
155.7, 139.0, 138.9, 131.3, 129.9, 127.3, 126.7, 124.5, 122.6, 122.5,
119.8, 116.4, 111.1, 55.9, 55.8, 16.5.
NMR (acetone-d6): d 193.4, 161.3, 160.4, 156.2, 155.6, 140.7, 139.3,
138.8, 130.7, 130.0, 124.5, 123.6, 119.9, 119.6, 116.6, 116.2, 113.0, 55.8,
55.6; IR: 2981, 1658, 1579, 1234 cmꢁ1; GC/MS m/z: 319 (M)þ.
4.6.46. [6-(4-Hydroxy-3-methylphenyl)-pyridin-2-yl]-(3-
hydroxyphenyl)-methanone (14)
4.6.50. (3-Hydroxyphenyl)-[6-(3-hydroxyphenyl)-pyridin-2-yl]-
methanone (16)
The title compound was prepared by reaction of [6-(4-methoxy-
3-methylphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-methanone
14a (341 mg, 1.02 mmol, 1 equiv) with boron tribromide
(10.2 mmol, 10 equiv) according to method E. The product was
purified by column chromatography (hexane/ethyl acetate 8:2)
then by preparative TLC (hexane/ethyl acetate 65:35) to afford
120 mg (38%) of the analytically pure compound as a yellow solid.
The title compound was prepared by reaction of (3-meth-
oxyphenyl)-[6-(3-methoxyphenyl)-pyridin-2-yl]-methanone 16a
(50 mg, 0.16 mmol, 1 equiv) with boron tribromide (1.6 mmol, 10
equiv) according to method E. The product was purified by
preparative TLC (hexane/ethyl acetate 1:1) to afford 32 mg (69%) of
the analytically pure product as a beige powder. C18H13NO3; MW
C19H15NO3; MW 305; 1H NMR (acetone-d6):
d
8.64 (s, br, 1H), 8.54
291; 1H NMR (acetone-d6):
d 8.68 (s, br,1H), 8.50 (s, br,1H), 8.13 (dd,
(s, br, 1H), 8.06 (dd, J ¼ 1.3 Hz, J ¼ 7.9 Hz, 1H), 8.04e8.00 (m, 1H),
7.93 (d, J ¼ 2.2 Hz, 1H), 7.85e7.81 (m, 2H), 7.67e7.63 (m, 2H),
7.41e7.37 (m, 1H), 7.14 (ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 7.9 Hz, 1H),
J ¼ 1.3 Hz, J ¼ 7.9 Hz, 1H), 8.11e8.07 (m, 1H), 7.90 (dd, J ¼ 1.3 Hz,
J ¼ 7.3 Hz, 1H), 7.66e7.63 (m, 2H), 7.63e7.62 (m, 1H), 7.61 (ddd,
J ¼ 0.9 Hz, J ¼ 1.6 Hz, J ¼ 7.6 Hz, 1H), 7.41e7.37 (m, 1H), 7.32 (t,
J ¼ 8.2 Hz, 1H), 7.14 (ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H), 6.93
(ddd, J ¼ 0.9 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H); 13C NMR (acetone-d6):
6.91 (d, J ¼ 8.2 Hz, 1H), 2.27 (s, 3H); 13C NMR (acetone-d6):
d 195.1,
157.0, 140.1, 140.0, 131.9, 131.6, 131.2, 127.8, 126.6, 124.5, 123.4, 123.3,
121.9, 119.5, 117.0, 17.5; IR: 3372, 1642, 1581, 1426 cmꢁ1; LC/MS m/z:
306 (M þ H)þ.
d
193.9, 158.8, 156.4, 156.1, 139.1, 138.7, 130.7, 130.1, 123.4, 123.3,
120.9, 119.0, 118.2, 117.4, 114.6; IR: 3282, 1641, 1581, 1325,
1213 cmꢁ1; LC/MS m/z: 292 (M þ H)þ.
4.6.47. (3-Methoxyphenyl)-[6-(2-methoxyphenyl)-pyridin-2-yl]-
methanone (15a)
4.6.51. [6-(4-Hydroxyphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-
methanone (17a)
The title compound was prepared by reaction of
(6-bromopyridin-2-yl)-(3-methoxyphenyl)-methanone 14b (100
mg, 0.34 mmol, 1 equiv) with 2-methoxyphenylboronic acid
(62 mg, 0.41 mmol, 1.2 equiv) according to method C. The product
was purified by column chromatography (hexane/ethyl acetate 8:2)
to afford 53 mg (49%) of the analytically pure product as a light
The title compound was prepared by reaction of (6-brom-
opyridin-2-yl)-(3-methoxyphenyl)-methanone 14b (150 mg,
0.51 mmol, 1 equiv) with 4-hydroxyphenylboronic acid (84 mg,
0.61 mmol, 1.2 equiv) according to method C. The product was
purified by column chromatography (hexane/ethyl acetate 8:2).
Yield: 45% (70 mg). C19H15NO3; MW 305; 1H NMR (acetone-d6):
yellow oil. C20H17NO3; MW 319; 1H NMR (acetone-d6):
d 8.19 (dd,
J ¼ 0.9 Hz, J ¼ 7.9 Hz, 1H), 8.05 (t, J ¼ 7.9 Hz, 1H), 7.94 (dd, J ¼ 1.2 Hz,
J ¼ 7.7 Hz,1H), 7.86 (dd, J ¼ 1.8 Hz, J ¼ 7.7 Hz,1H), 7.78e7.76 (m, 1H),
7.76e7.73 (m, 1H), 7.46e7.40 (m, 2H), 7.21 (ddd, J ¼ 1.0 Hz,
J ¼ 2.6 Hz, J ¼ 8.2 Hz, 1H), 7.17 (dd, J ¼ 0.9 Hz, J ¼ 8.5 Hz, 1H), 7.05
(dt, J ¼ 1.2 Hz, J ¼ 7.6 Hz, 1H), 3.93 (s, 3H), 3.86 (s, 3H); 13C NMR
d
8.73 (s, br, 1H), 8.09 (dd, J ¼ 1.2 Hz, J ¼ 8.0 Hz, 1H), 8.06 (d,
J ¼ 7.5 Hz, 1H), 8.04e8.01 (m, 2H), 7.87 (dd, J ¼ 1.5 Hz, J ¼ 7.3 Hz,
1H), 7.76e7.72 (m, 2H), 7.47 (t, J ¼ 7.8 Hz, 1H), 7.23 (ddd, J ¼ 1.0 Hz,
J ¼ 2.7 Hz, J ¼ 8.3 Hz, 1H), 6.97e6.93 (m, 2H), 3.87 (s, 3H); 13C NMR
(acetone-d6):
d 193.7, 160.4, 159.9, 156.5, 155.7, 139.0, 138.9, 130.7,
(acetone-d6):
d
193.6, 160.4, 158.4, 155.8, 155.6, 138.9, 137.9, 131.9,
130.0, 129.2, 124.5, 122.4, 122.3, 119.8, 116.5, 116.2, 55.8; GC/MS m/z:
131.3, 129.9, 128.9, 128.3, 124.5, 122.9, 121.6, 119.7, 116.4, 112.7, 56.0,
305 (M)þ.
55.8; LC/MS m/z : 320 (M þ H)þ.
4.6.52. (3-Hydroxyphenyl)-[6-(4-hydroxyphenyl)-pyridin-2-yl]-
methanone (17)
4.6.48. (3-Hydroxyphenyl)-[6-(2-hydroxyphenyl)-pyridin-2-yl]-
methanone (15)
The title compound was prepared by reaction of [6-(4-
hydroxyphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-methanone 17a
(30 mg, 0.10 mmol, 1 equiv) with boron tribromide (0.50 mmol, 5
equiv) according to method E. The product was recrystallised in
ethyl acetate to afford 15 mg (51%) of the analytically pure
compound. C18H13NO3; MW 291; mp: 177e179 ꢀC; 1H NMR
The title compound was prepared by reaction of (3-meth-
oxyphenyl)-[6-(2-methoxyphenyl)-pyridin-2-yl]-methanone 15a
(40 mg, 0.13 mmol, 1 equiv) with boron tribromide (1.3 mmol, 10
equiv) according to method E. The product was purified by
preparative TLC (hexane/ethyl acetate 1:1). Yield: 30 mg (79%).
White oil. C18H13NO3; MW 291; 1H NMR (acetone-d6):
d
8.42 (d,
(acetone-d6 þ MeOH):
d 8.21e8.16 (m, 1H), 8.15e8.11 (m, 1H), 7.94
J ¼ 7.9 Hz, 1H), 8.28e8.24 (m, 1H), 8.06 (dd, J ¼ 1.5 Hz, J ¼ 8.1 Hz,
1H), 7.94 (dd, J ¼ 0.7 Hz, J ¼ 7.5 Hz, 1H), 7.43e7.41 (m, 3H),
7.35e7.30 (m, 1H), 7.19e7.16 (m, 1H), 6.97e6.93 (m, 1H), 6.88 (dd,
J ¼ 1.2 Hz, J ¼ 8.2 Hz, 1H); GC/MS m/z: 291 (M)þ.
(d, J ¼ 8.9 Hz, 2H), 7.90 (s, 1H), 7.52 (d, J ¼ 7.9 Hz, 1H), 7.50e7.48 (m,
1H), 7.35 (t, J ¼ 8.1 Hz, 1H), 7.11e7.08 (m, 1H), 6.91 (d, J ¼ 8.5 Hz,
2H); IR: 3140, 1605, 1453, 1340, 1193 cmꢁ1; LC/MS m/z: 292
(M þ H)þ.
4.6.49. (3-Methoxyphenyl)-[6-(3-methoxyphenyl)-pyridin-2-yl]-
methanone (16a)
4.6.53. [6-(4-Methoxy-2-methylphenyl)-pyridin-2-yl]-(3-
methoxyphenyl)-methanone (18a)
The title compound was prepared by reaction of (6-brom-
opyridin-2-yl)-(3-methoxyphenyl)-methanone 14b (150 mg,
0.51 mmol, 1 equiv) with 3-methoxyphenylboronic acid (94 mg,
0.62 mmol, 1.2 equiv) according to method C. The product was
purified by column chromatography (hexane/ethyl acetate 8:2).
Yield: 70 mg (43%). C20H17NO3; MW 319; 1H NMR (acetone-d6):
The title compound was prepared by reaction of
(6-bromopyridin-2-yl)-(3-methoxyphenyl)-methanone 14b (200
mg, 0.68 mmol, 1 equiv) with 4-methoxy-2-methylphenylboronic
acid (136 mg, 0.82 mmol, 1.2 equiv) according to method D. The
product was purified by column chromatography (hexane/ethyl
acetate 7:3) to afford 100 mg (44%) of the analytically pure
d
8.19 (dd, J ¼ 1.1 Hz, J ¼ 7.9 Hz, 1H), 8.12 (t, J ¼ 7.9 Hz, 1H), 7.99 (dd,
compound. C21H19NO3; MW 333; 1H NMR (acetone-d6):
(t, J ¼ 7.9 Hz, 1H), 7.94 (dd, J ¼ 0.9 Hz, J ¼ 7.6 Hz, 1H), 7.73 (dd,
d 8.08
J ¼ 0.9 Hz, J ¼ 7.6 Hz, 1H), 7.79e7.74 (m, 3H), 7.70 (ddd, J ¼ 0.9 Hz,

M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
13
J ¼ 0.9 Hz, J ¼ 7.9 Hz, 1H), 7.70e7.66 (m, 2H), 7.46e7.43 (m, 1H),
4.6.58. [6-(3-Fluoro-4-hydroxyphenyl)-pyridin-2-yl]-(3-
hydroxyphenyl)-methanone (20)
7.43e7.39 (m, 1H), 7.18 (ddd, J ¼ 1.3 Hz, J ¼ 2.5 Hz, J ¼ 8.2 Hz, 1H),
6.87e6.84 (m, 2H), 3.84 (s, 3H), 3.83 (s, 3H), 2.39 (s, 3H); 13C NMR
The title compound was prepared by reaction of [6-(3-fluoro-
4-methoxyphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-methanone
20a (120 mg, 0.36 mmol, 1 equiv) with pyridinium hydrochloride
(36 mmol, 100 equiv) according to method G. The analytically
pure product was obtained after recrystallisation with hexane and
ethyl acetate as a brown solid. Yield: 103 mg (94%). C18H12FNO3;
(acetone-d6):
d 160.4, 159.4, 155.7, 139.0, 138.5, 138.4, 132.1, 129.8,
127.2, 124.3, 122.4, 119.5, 117.2, 117.1, 116.3, 112.2, 112.1, 55.7, 55.5,
14.4; IR: 2959, 1661, 1579, 1450, 1237 cmꢁ1
333 (M)þ.
; GC/MS m/z:
4.6.54. [6-(4-Hydroxy-2-methylphenyl)-pyridin-2-yl]-(3-
hydroxyphenyl)-methanone (18)
MW 309; mp: 224e226 ꢀC; 1H NMR (acetone-d6):
d 8.32 (d,
J ¼ 1.9 Hz, 1H), 7.89e7.87 (m, 1H), 7.75e7.74 (m, 1H), 7.38 (dd,
J ¼ 2.2 Hz, J ¼ 8.2 Hz, 1H), 7.21 (t, J ¼ 1.6 Hz, 1H), 7.19 (dd,
J ¼ 0.6 Hz, J ¼ 8.2 Hz, 1H), 7.15 (t, J ¼ 1.6 Hz, 1H), 6.80 (dd,
J ¼ 0.6 Hz, J ¼ 1.6 Hz, 1H), 6.60 (dd, J ¼ 0.9 Hz, J ¼ 1.9 Hz, 1H),
The title compound was prepared by reaction of [6-(4-
methoxy-2-methylphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-
methanone 18a (90 mg, 0.27 mmol, 1 equiv) with boron tri-
bromide (2.7 mmol, 10 equiv) according to method E. The
product was purified by column chromatography (hexane/ethyl
acetate 7:3) to afford 45 mg (55%) of the analytically pure
compound as a brown oil. C19H15NO3; MW 305; 1H NMR
5.35 (d, J ¼ 8.2 Hz, 1H); 13C NMR (acetone-d6):
d 183.5, 164.7,
161.0, 160.4, 156.5, 149.4, 147.7, 143.6, 143.3, 139.0, 132.2, 129.5,
120.9; IR: 3225, 3027, 1608, 1468, 1285 cmꢁ1; LC/MS m/z: 310
(M þ H)þ.
(acetone-d6): d 8.60 (s, br, 1H), 8.43 (s, br, 1H), 8.05e8.00 (m, 1H),
7.85 (dd, J ¼ 1.1 Hz, J ¼ 7.8 Hz, 1H), 7.69 (dd, J ¼ 0.9 Hz, J ¼ 7.8 Hz,
1H), 7.55e7.50 (m, 2H), 7.35e7.28 (m, 2H), 7.07 (dd, J ¼ 0.9 Hz,
J ¼ 8.1 Hz, 1H), 6.76e6.69 (m, 2H), 2.32 (s, 3H); 13C NMR
4.6.59. [6-(3-Chloro-4-hydroxyphenyl)-pyridin-2-yl]-(3-
methoxyphenyl)-methanone (21a)
Thetitlecompoundwasprepared byreactionof(6-bromopyridin-
2-yl)-(3-methoxyphenyl)-methanone 14b (200 mg, 0.68 mmol,
1 equiv) with 3-chloro-4-hydroxyphenylboronic acid (141 mg,
0.82 mmol, 1.2 equiv) according to method D. The product was
purified by column chromatography (hexane/ethyl acetate 7:3) to
afford 120 mg (50%) of the analytically pure compound as white oil.
(acetone-d6):
d 158.6, 158.0, 138.3, 132.3, 129.9, 127.0, 123.2,
122.1, 120.7, 118.4, 118.0, 113.8, 21.2; IR: 3255, 2924, 1689, 1583,
1219 cmꢁ1; LC/MS m/z: 306 (M þ H)þ.
4.6.55. [6-(2-Fluoro-4-methoxyphenyl)-pyridin-2-yl]-(3-
methoxyphenyl)-methanone (19a)
C19H14ClNO3; MW339; 1H NMR (acetone-d6):
d 9.13 (s, br,1H), 8.18 (d,
Thetitlecompoundwaspreparedbyreactionof(6-bromopyridin-
2-yl)-(3-methoxyphenyl)-methanone 14b (170 mg, 0.58 mmol,
1 equiv) with 2-fluoro-4-methoxyphenylboronic acid (119 mg,
0.70mmol,1.2equiv)accordingto method D. The productwasusedin
the next step without further purification. C20H16FNO3; MW 337.
J¼ 2.2Hz,1H), 8.15 (dd,J ¼ 0.8 Hz,J ¼ 8.0 Hz,1H), 8.10(t, J¼ 7.7Hz,1H),
7.97 (dd, J ¼ 2.1 Hz, J ¼ 8.4 Hz,1H), 7.93 (dd, J ¼ 0.9 Hz, J ¼ 7.5 Hz,1H),
7.76e7.74 (m,1H), 7.73e7.70 (m,1H), 7.48 (t, J ¼ 8.0 Hz,1H), 7.25 (ddd,
J ¼ 0.6 Hz, J ¼ 2.8 Hz, J ¼ 8.2 Hz,1H), 7.13 (d, J ¼ 8.5 Hz,1H), 3.88(s, 3H);
13C NMR (acetone-d6):
d 193.5, 155.7, 155.2, 155.1, 139.3, 132.1, 130.0,
129.3, 128.5, 127.5, 126.9, 124.4, 123.0, 122.7, 120.0, 118.0, 117.9, 116.2,
4.6.56. [6-(2-Fluoro-4-hydroxyphenyl)-pyridin-2-yl]-(3-
hydroxyphenyl)-methanone (19)
55.8; GC/MS m/z: 339e341 (M)þ.
The title compound was prepared by reaction of [6-(2-fluoro-
4-methoxyphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-meth-
anone 19a (100 mg, 0.3 mmol, 1 equiv) with boron tribromide
(3.0 mmol, 10 equiv) according to method E. The product was
recrystallised in ethyl acetate to afford 50 mg (54%) of the
analytically pure product as a yellow powder. C18H12FNO3; MW
4.6.60. [6-(3-Chloro-4-hydroxyphenyl)-pyridin-2-yl]-(3-
hydroxyphenyl)-methanone (21)
The title compound was prepared by reaction of [6-(3-chloro-4-
hydroxyphenyl)-pyridin-2-yl]-(3-methoxyphenyl)-methanone 21a
(200 mg, 0.59 mmol, 1 equiv) with pyridinium hydrochloride
(59 mmol, 100 equiv) according to method G. The product was
purified by recrystallisation in ethanol and ethyl acetate to give
82 mg (43%) of the analytically pure compound as a green powder.
C18H12ClNO3; MW 325; mp: 206e208 ꢀC; 1H NMR (acetone-d6):
309; mp: 246e248 ꢀC; 1H NMR (acetone-d6):
d 8.27e8.22 (m,
1H), 8.11e8.08 (m, 1H), 7.98e7.95 (m, 1H), 7.84 (t, J ¼ 8.2 Hz, 1H),
7.49 (dt, J ¼ 1.1 Hz, J ¼ 7.8 Hz, 1H), 7.47e7.45 (m, 1H), 7.33 (t,
J ¼ 7.9 Hz, 1H), 7.11e7.07 (m, 1H), 6.77e6.73 (m, 1H), 6.69e6.64
d
9.10 (s, br, 1H), 8.76 (s, br, 1H), 8.17 (d, J ¼ 2.2 Hz, 1H), 8.13 (dd,
(m, 1H); 13C NMR (acetone-d6):
d
158.7, 137.0, 133.3, 130.8, 129.7,
J ¼ 0.9 Hz, J ¼ 7.9 Hz, 1H), 8.10e8.06 (m, 1H), 7.97 (dd, J ¼ 2.2 Hz,
J ¼ 8.5 Hz, 1H), 7.88 (dd, J ¼ 0.9 Hz, J ¼ 7.6 Hz, 1H), 7.64e7.60 (m,
2H), 7.42e7.38 (m, 1H), 7.15 (ddd, J ¼ 1.3 Hz, J ¼ 2.2 Hz, J ¼ 7.9 Hz,
128.9, 125.9, 122.8, 122.3, 119.3, 119.2, 118.4, 118.2, 117.5, 113.7,
108.2, 104.7; IR: 3251, 3027, 1608, 1468, 1235 cmꢁ1; LC/MS m/z:
310 (M þ H)þ.
1H), 7.13 (d, J ¼ 8.5 Hz, 1H); 13C NMR (acetone-d6):
d 193.8, 158.1,
156.0, 155.2, 155.1, 139.2, 132.2, 130.1, 129.4, 127.5, 123.3, 122.9,
122.5, 121.8, 120.9, 118.2, 117.8; IR: 3345, 1639, 1580, 1324,
1290 cmꢁ1; LC/MS m/z: 326 (M þ H)þ.
4.6.57. [6-(3-Fluoro-4-methoxyphenyl)-pyridin-2-yl]-(3-
methoxyphenyl)-methanone (20a)
Thetitlecompoundwaspreparedbyreactionof(6-bromopyridin-
2-yl)-(3-methoxyphenyl)-methanone 14b (150 mg, 0.51 mmol,
1 equiv) with 3-fluoro-4-methoxyphenylboronic acid (104 mg,
0.61 mmol, 1.2 equiv) according to method D. The product was
recrystallised in ethanol to afford 130 mg (76%) of the analytically
pure compound as a white powder. C20H16FNO3; MW 337; mp:
4.6.61. (6-Bromopyridin-2-yl)-(4-fluoro-3-methoxyphenyl)-
methanol (22c)
To a solution of 5-bromo-2-fluoroanisole (200 mg, 0.98 mmol,
1 equiv) in anhydrous THF was added granules of magnesium (24 mg,
0.98 mmol, 1 equiv) under nitrogen. The mixture was heated to
60 ꢀC for 2 h. After reaching room temperature, 6-bromopyridin-2-
yl carboxaldehyde (182 mg, 0.98 mmol, 1 equiv) was added and the
reaction mixture was heated to 80 ꢀC and stirred overnight at 80 ꢀC.
The reaction was cooled to room temperature, quenched with brine
and the aqueous layer was extracted with ethyl acetate. The
combined organic layers were dried over sodium sulfate, filtered
and concentrated to dryness under vacuum. The product was used
100e102 ꢀC; 1H NMR (acetone-d6):
d
8.17 (dd, J ¼ 1.3 Hz, J ¼ 8.2 Hz,
1H), 8.10 (t, J ¼ 7.6 Hz, 1H), 7.97e7.94 (m, 2H), 7.92 (dd, J ¼ 1.3 Hz,
J ¼ 5.7 Hz, 1H), 7.74e7.70 (m, 2H), 7.50e7.46 (m, 1H), 7.28e7.23 (m,
2H), 3.95 (s, 3H), 3.88 (s, 3H); 13C NMR (acetone-d6):
d 193.5, 160.5,
155.7, 155.1, 152.4, 149.9, 139.3, 138.8, 132.4, 130.0, 124.4, 123.9, 123.2,
122.8, 119.9, 116.2, 115.1, 114.9, 56.6, 55.8; IR: 2926, 1662, 1581,
1283 cmꢁ1; GC/MS m/z: 337 (M)þ.

14
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
in the next step without further purification. C13H11BrFNO2; MW
312.
dried over sodium sulfate, filtered and concentrated to dryness
under vacuum. The product was purified by column chromatog-
raphy (hexane/ethyl acetate 8:2) to afford the analytically pure
compound in 76% yield (232 mg) as a yellow oil. C14H14BrNO2;
4.6.62. (6-Bromopyridin-2-yl)-(4-fluoro-3-methoxyphenyl)-
methanone (22b)
MW 308; 1H NMR (acetone-d6):
d
7.71 (t, J ¼ 7.8 Hz, 1H), 7.60 (d,
The titlecompoundwaspreparedbyreactionof(6-bromopyridin-
2-yl)-(4-fluoro-3-methoxyphenyl)-methanol 22c (150 mg, 0.48 mmol,
1 equiv) with 2-iodoxybenzoic acid (269 mg, 0.96 mmol, 2 equiv)
according to method B. The product was purified by column chro-
matography (hexane/ethyl acetate 7:3) to afford 130 mg (87%) of the
analytically pure compound as orange oil. C13H9BrFNO2; MW 310;
J ¼ 7.7 Hz, 1H), 7.44 (d, J ¼ 7.9 Hz, 1H), 7.07e7.04 (m, 2H), 6.89 (dd,
J ¼ 1.3 Hz, J ¼ 7.5 Hz, 1H), 5.75 (d, J ¼ 4.5 Hz, 1H), 5.11 (d, J ¼ 4.5 Hz,
1H), 3.80 (s, 3H), 2.12 (s, 3H); 13C NMR (acetone-d6):
d 166.6, 158.6,
143.4, 141.3, 140.6, 131.0, 127.2, 126.0, 120.3, 119.2, 109.3, 76.5, 55.6,
16.0; IR: 3396, 2923, 1581, 1555, 1252 cmꢁ1
; GC/MS m/z:
307e309 (M)þ.
1H NMR (acetone-d6):
d
8.05 (dd, J ¼ 1.3 Hz, J ¼ 7.6 Hz, 1H), 8.02
(t, J ¼ 7.6 Hz, 1H), 7.94 (dd, J ¼ 2.2 Hz, J ¼ 8.5 Hz, 1H), 7.89 (dd,
J ¼ 1.3 Hz, J ¼ 7.6 Hz, 1H), 7.74 (ddd, J ¼ 2.2 Hz, J ¼ 4.4 Hz, J ¼ 8.5 Hz,
4.6.66. (6-Bromopyridin-2-yl)-(3-methoxy-4-methylphenyl)-
methanone (23b)
1H), 7.33e7.28 (m, 1H), 3.98 (s, 3H); 13C NMR (acetone-d6):
d
190.3,
The title compound was prepared by reaction of
(6-bromopyridin-2-yl)-(3-methoxy-4-methylphenyl)-methanol 23c
(60 mg, 0.19 mmol, 1 equiv) with 2-iodoxybenzoic acid (106 mg,
0.38 mmol, 2 equiv) according to method B. The product was
purified by column chromatography (hexane/ethyl acetate 8:2) to
afford the analytically pure compound in 98% yield (57 mg) as
a yellow powder. C14H12BrNO2; MW 306; 1H NMR (acetone-d6):
157.4,156.5,148.5,141.3,141.0,133.4,132.0,126.0,124.5,116.7,108.3,
56.6; IR: 3058, 1686, 1585, 1514, 1421, 1293 cmꢁ1; LC/MS m/z:
310e312 (M þ H)þ.
4.6.63. (4-Fluoro-3-methoxyphenyl)-[6-(4-methoxy-3-
methylphenyl)-pyridin-2-yl]-methanone (22a)
The titlecompoundwaspreparedbyreactionof(6-bromopyridin-
2-yl)-(4-fluoro-3-methoxyphenyl)-methanone 22b (100 mg,
0.32 mmol, 1 equiv) with 4-methoxy-3-methylphenylboronic acid
(64 mg, 0.39 mmol, 1.2 equiv) according to method D. The product
was purified by column chromatography (hexane/ethyl acetate 7:3)
to give 70 mg (62%) of the analytically pure compound. C21H18FNO3;
d
8.03e8.01 (m, 1H), 8.00 (d, J ¼ 1.4 Hz, 1H), 7.89e7.85 (m, 1H), 7.69
(d, J ¼ 1.4 Hz, 1H), 7.58 (dd, J ¼ 1.5 Hz, J ¼ 7.7 Hz, 1H), 7.30 (dd,
J ¼ 0.9 Hz, J ¼ 7.7 Hz, 1H), 3.92 (s, 3H), 2.28 (s, 3H); 13C NMR
(acetone-d6):
d 191.5, 158.5, 157.1, 141.2, 141.1, 135.7, 133.6, 131.6,
131.0, 124.8, 124.3, 112.4, 55.8, 16.6; IR: 2929, 1651, 1553, 1302,
1247 cmꢁ1; LC/MS m/z: 306e308 (M þ H)þ.
MW 351; 1H NMR (acetone-d6):
d
8.13 (dd, J ¼ 1.1 Hz, J ¼ 7.8 Hz, 1H),
8.09e8.04 (m, 2H), 7.99 (dd, J ¼ 2.3 Hz, J ¼ 8.6 Hz, 1H), 7.97 (d,
J ¼ 1.7 Hz, 1H), 7.91 (dd, J ¼ 1.0 Hz, J ¼ 7.6 Hz, 1H), 7.88e7.84 (m, 1H),
7.35e7.30 (m,1H), 7.05 (d, J ¼ 8.6Hz,1H), 3.97 (s, 3H), 3.90(s, 3H), 2.25
4.6.67. (3-Methoxy-4-methylphenyl)-[6-(4-methoxy-3-
methylphenyl)-pyridin-2-yl]-methanone (23a)
The title compound was prepared by reaction of
(6-bromopyridin-2-yl)-(3-methoxy-4-methylphenyl)-methanone
(s, 3H); 13C NMR (acetone-d6):
d 190.1, 160.1, 156.5, 155.5, 139.1, 129.8,
127.4,126.7,126.1,122.7,122.6,117.0,116.4,116.2,111.1, 56.6, 55.9,16.5;
23b (50 mg, 0.16 mmol,
1
equiv) with 4-methoxy-3-
LC/MS m/z: 352 (M þ H)þ.
methylphenylboronic acid (31 mg, 0.19 mmol, 1.2 equiv) accord-
ing to method D. The product was purified by column chroma-
tography (hexane/ethyl acetate 7:3) to afford the analytically pure
compound in 68% yield (38 mg) as an orange powder. C22H21NO3;
4.6.64. (4-Fluoro-3-hydroxyphenyl)-[6-(4-hydroxy-3-
methylphenyl)-pyridin-2-yl]-methanone (22)
The title compound was prepared by reaction of (4-fluoro-3-
methoxyphenyl)-[6-(4-methoxy-3-methylphenyl)-pyridin-2-yl]-
methanone 22a (30 mg, 0.09 mmol, 1 equiv) with pyridinium
hydrochloride (9 mmol, 100 equiv) according to method G. The
analytically pure product was obtained after purification by
column chromatography (hexane/ethyl acetate 7:3) and prepar-
ative HPLC using isopropanol/water as eluent in 66% yield
MW 347; 1H NMR (acetone-d6):
d
8.11 (dd, J ¼ 0.9 Hz, J ¼ 8.1 Hz,
1H), 8.05 (t, J ¼ 7.5 Hz, 1H), 8.01e7.97 (m, 2H), 7.86 (dd, J ¼ 0.9 Hz,
J ¼ 7.5 Hz, 1H), 7.82 (d, J ¼ 1.6 Hz, 1H), 7.71 (dd, J ¼ 1.4 Hz, J ¼ 7.7 Hz,
1H), 7.32 (dd, J ¼ 0.6 Hz, J ¼ 7.7 Hz, 1H), 7.04 (d, J ¼ 8.5 Hz, 1H), 3.91
(s, 3H), 3.90 (s, 3H), 2.29 (s, 3H), 2.24 (s, 3H); 13C NMR (acetone-
d6):
d 193.2, 160.1, 158.4, 156.4, 156.1, 139.0, 133.0, 131.4, 130.8,
129.8, 127.3, 125.0, 122.5, 122.4, 113.3, 112.6, 112.1, 111.1, 55.9, 55.8,
16.6, 16.5; IR: 2916, 1651, 1566, 1233 cmꢁ1; LC/MS m/z: 348
(M þ H)þ.
(19 mg). C19H14FNO3; MW 323; 1H NMR (acetone-d6):
d 9.01 (s, br,
1H), 8.57 (s, br, 1H), 8.07 (dd, J ¼ 1.3 Hz, J ¼ 8.2 Hz, 1H), 8.05e8.01
(m, 1H), 7.93 (dd, J ¼ 0.6 Hz, J ¼ 2.2 Hz, 1H), 7.90 (dd, J ¼ 2.2 Hz,
J ¼ 8.8 Hz, 1H), 7.85e7.82 (m, 2H), 7.75 (ddd, J ¼ 2.2 Hz, J ¼ 4.7 Hz,
J ¼ 8.5 Hz, 1H), 7.32e7.27 (m, 1H), 6.93 (d, J ¼ 8.2 Hz, 1H), 2.27 (s,
4.6.68. (3-Hydroxy-4-methylphenyl)-[6-(4-hydroxy-3-
methylphenyl)-pyridin-2-yl]-methanone (23)
3H); 13C NMR (acetone-d6):
d
193.2, 163.8, 158.0, 157.9, 156.8,
The title compound was prepared by reaction of (3-methoxy-
4-methylphenyl)-[6-(4-methoxy-3-methylphenyl)-pyridin-2-yl]-
methanone 23a (30 mg, 0.09 mmol, 1 equiv) with boron tri-
fluoride dimethylsulfide complex (6.3 mmol, 70 equiv) according
to method F. The product was purified by column chromatography
(hexane/ethyl acetate 7:3) then by preparative HPLC with iso-
propanol/water as eluent to afford 10 mg (35%) of the analytically
pure compound as a white powder. C20H17NO3; MW 319; 1H NMR
155.6, 139.0, 130.5, 126.6, 124.9, 122.4, 122.3, 122.2, 118.8, 116.6,
116.5, 115.9, 16.4; IR: 3332, 1656, 1583, 1181 cmꢁ1; LC/MS m/z: 324
(M þ H)þ.
4.6.65. (6-Bromopyridin-2-yl)-(3-methoxy-4-methylphenyl)-
methanol (23c)
To a solution of 5-bromo-2-methylanisole (200 mg, 0.99 mmol,
1 equiv) in anhydrous THF was added granules of magnesium
(24 mg, 0.99 mmol, 1 equiv) under nitrogen. The mixture was
heated to 60 ꢀC for 2 h. After cooling down to room temperature,
6-bromopyridin-2-yl carboxaldehyde (182 mg, 0.99 mmol,
1 equiv) was added and the reaction mixture was heated to 80 ꢀC
and stirred overnight at 80 ꢀC. The reaction was cooled to room
temperature, quenched with brine and the aqueous layer was
extracted with ethyl acetate. The combined organic layers were
(acetone-d6):
d
8.60 (s, br, 2H), 8.05 (dd, J ¼ 1.4 Hz, J ¼ 8.0 Hz, 1H),
8.01 (t, J ¼ 8.3 Hz, 1H), 7.94e7.92 (m, 1H), 7.84 (dd, J ¼ 2.1 Hz,
J ¼ 8.4 Hz, 1H), 7.77 (dd, J ¼ 1.3 Hz, J ¼ 7.3 Hz, 1H), 7.66 (d,
J ¼ 1.6 Hz, 1H), 7.61 (dd, J ¼ 1.8 Hz, J ¼ 7.8 Hz, 1H), 7.27 (d,
J ¼ 7.8 Hz, 1H), 6.93 (d, J ¼ 8.3 Hz, 1H), 2.31 (s, 3H), 2.26 (s, 3H); 13C
NMR (acetone-d6):
d 190.9, 174.6, 161.0, 138.8, 131.2, 130.4, 126.6,
123.7, 122.0, 121.9, 118.8, 16.5, 16.4; IR: 3340, 1671, 1585 cmꢁ1; LC/
MS m/z: 320 (M þ H)þ.

M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
15
4.6.69. (6-Bromopyridin-2-yl)-(5-fluoro-3-methoxyphenyl)-
methanol (24c)
1H), 7.63e7.59 (m, 1H), 7.32e7.30 (m, 1H), 7.22 (ddd, J ¼ 1.3 Hz,
J ¼ 2.2 Hz, J ¼ 9.5 Hz,1H), 6.71 (d, J ¼ 8.5 Hz,1H), 6.68 (dt, J ¼ 2.2 Hz,
To a solution of 3-bromo-5-fluoroanisole (250 mg, 1.22 mmol,
1 equiv) in anhydrous THF was added granules of magnesium
(32 mg, 1.28 mmol, 1.05 equiv) under nitrogen. The mixture was
heated to 60 ꢀC for 2 h. After cooling down to room temperature,
6-bromopyridin-2-yl carboxaldehyde (271 mg, 1.47 mmol, 1.2
equiv) was added and the reaction mixture was stirred at 80 ꢀC
overnight. The reaction was cooled to room temperature, quenched
with brine and the aqueous layer was extracted with ethyl acetate.
The combined organic layers were dried over sodium sulfate,
filtered and concentrated to dryness under vacuum. The product
was purified by column chromatography (hexane/ethyl acetate 8:2)
to afford the analytically pure compound in 21% yield (80 mg).
J ¼ 10.4 Hz, 1H), 2.27 (s, 3H); 13C NMR (acetone-d6):
d 192.4, 164.9,
159.6, 159.5, 155.1, 140.1, 140.0, 139.0, 130.6, 130.5, 126.6, 122.7,
122.3, 115.9, 115.1, 109.6, 109.4, 107.8, 16.4; IR: 3399, 2921, 1613,
1584, 1146 cmꢁ1; LC/MS m/z: 324 (M þ H)þ.
4.7. Biological assays
[2,4,6,7-3H]-E2 and [2,4,6,7-3H]-E1 were bought from Per-
kineElmer, Boston. Quickszint Flow 302 scintillator fluid was
bought from Zinsser Analytic, Frankfurt. 17b-HSD2 and 17b-HSD1
were obtained from human placenta according to previously
described procedures [46,48,49]. Fresh human placenta was
homogenised and centrifuged. The pellet fraction contains the
C13H11BrFNO2; MW 312; 1H NMR (acetone-d6):
d
7.74 (t, J ¼ 7.6 Hz,
1H), 7.64e7.61 (m, 1H), 7.47 (dd, J ¼ 0.9 Hz, J ¼ 7.2 Hz, 1H),
6.92e6.90 (m, 1H), 6.81 (ddd, J ¼ 0.6 Hz, J ¼ 1.3 Hz, J ¼ 9.1 Hz, 1H),
6.59 (dt, J ¼ 2.5 Hz, J ¼ 10.7 Hz, 1H), 5.77 (d, J ¼ 4.7 Hz, 1H), 5.35 (d,
microsomal 17b-HSD2, while 17b-HSD1 was obtained after
precipitation with ammonium sulfate from the cytosolic fraction.
J ¼ 4.7 Hz, 1H), 3.79 (s, 3H); 13C NMR (acetone-d6):
d
165.8, 165.3,
4.7.1. Inhibition of 17b-HSD2
140.8, 127.5, 120.3, 109.4, 106.1, 105.9, 101.0, 100.8, 75.8, 56.0; LC/MS
Inhibitory activities were evaluated by a well established
m/z: 312e314 (M þ H)þ.
method with minor modifications [44,46,48,50]. Briefly, the
microsomal enzyme was incubated with NADþ [1500
mM] in the
4.6.70. (6-Bromopyridin-2-yl)-(5-fluoro-3-methoxyphenyl)-
methanone (24b)
presence of potential inhibitors at 37 ꢀC in a phosphate buffer
(50 mM) supplemented with 20% of glycerol and EDTA 1 mM.
Inhibitor stock solutions were prepared in DMSO. Final concen-
tration of DMSO was adjusted to 1% in all samples. The enzymatic
reaction was started by addition of a mixture of unlabeled- and
Thetitlecompoundwaspreparedbyreactionof(6-bromopyridin-
2-yl)-(5-fluoro-3-methoxyphenyl)-methanol 24c (190 mg, 0.61 mmol,
1 equiv) with 2-iodoxybenzoic acid (342 mg, 1.22 mmol, 2 equiv)
according to method B. The product was purified by column chro-
matography (hexane/ethyl acetate 17:3) to afford 150 mg (79%) of
the analytically pure compound as a brown solid. C13H9BrFNO2; MW
[2,4,6,7-3H]-E2 (final concentration: 500 nM, 0.11
mCi). After 20 min
at 37 ꢀC, the incubation was stopped with HgCl2 and the mixture
was extracted with ether. After evaporation, the steroids were
dissolved in acetonitrile/water (45:55). E1 and E2 were separated
using acetonitrile/water (45:55) as mobile phase in a C18 rp chro-
310; 1H NMR (acetone-d6):
d
8.08 (dd, J ¼ 0.9 Hz, J ¼ 7.6 Hz,1H), 8.03
(t, J ¼ 7.6 Hz, 1H), 7.91 (dd, J ¼ 0.9 Hz, J ¼ 7.6 Hz, 1H), 7.53e7.51 (m,
1H), 7.41 (ddd, J ¼ 1.3 Hz, J ¼ 2.5 Hz, J ¼ 9.1 Hz,1H), 7.05 (dt, J ¼ 2.2 Hz,
matography column (Nucleodur C18 Gravity, 3
mm, Macherey-
J ¼ 10.4 Hz, 1H), 3.91 (s, 3H); 13C NMR (acetone-d6):
d
190.6, 164.9,
Nagel, Düren) connected to a HPLC-system (Agilent 1100 Series,
Agilent Technologies, Waldbronn). Detection and quantification of
the steroids were performed using a radioflow detector (Berthold
Technologies, Bad Wildbad). The conversion rate was calcula-
ted according to following equation: %conversion ¼ ð%ðE1Þ
=ð%ðE1Þ þ %ðE2ÞÞÞ ꢃ 100. Each value was calculated from at least
three independent experiments.
161.9, 161.8, 141.4, 132.2, 124.6, 110.2, 107.0, 56.4; IR: 3080, 2980,
1668, 1555, 1152 cmꢁ1; LC/MS m/z: 310e312 (M þ H)þ.
4.6.71. (5-Fluoro-3-methoxyphenyl)-[6-(4-methoxy-3-
methylphenyl)-pyridin-2-yl]-methanone (24a)
Thetitlecompoundwaspreparedbyreactionof(6-bromopyridin-
2-yl)-(5-fluoro-3-methoxyphenyl)-methanone 24b (80 mg, 0.26 mmol,
1 equiv) with 4-methoxy-3-methylphenylboronic acid (52 mg,
0.31 mmol, 1.2 equiv) according to method D. The analytically pure
product was obtained after purification by column chromatography
(gradient hexane/ethyl acetate from 1:0 to 8:2) in 81% yield (74 mg).
4.7.2. Inhibition of 17
The 17 -HSD1 inhibition assay was performed similarly to the
-HSD2 procedure. The cytosolic fraction was incubated with
NADH [500 M], test compound and a mixture of unlabeled- and
[2,4,6,7-3H]-E1 (final concentration: 500 nM, 0.15
Ci) for 10 min.
b-HSD1
b
17b
m
C21H18FNO3; MW 351; 1H NMR (acetone-d6):
d
8.13 (dd, J ¼ 1.3 Hz,
m
J ¼ 8.2 Hz, 1H), 8.07 (t, J ¼ 7.9 Hz, 1H), 7.99e7.96 (m, 2H), 7.93 (dd,
J ¼ 0.9 Hz, J ¼ 7.6 Hz, 1H), 7.66e7.64 (m, 1H), 7.54 (ddd, J ¼ 1.3 Hz,
J ¼ 2.5 Hz, J ¼ 9.5 Hz, 1H), 7.06e7.05 (m, 1H), 7.04e7.02 (m, 1H),
Further treatment of the samples and HPLC separation was carried
out as mentioned above.
3.91 (s, 3H), 3.90 (s, 3H), 2.25 (s, 3H); 13C NMR (acetone-d6):
d
192.1,
4.7.3. ER affinity
161.8, 161.7, 160.2, 154.9, 139.2, 131.2, 129.9, 127.4, 126.7, 123.0,
122.7,113.5,111.1,110.7,110.5,106.7,106.5, 56.4, 55.9, 16.5; LC/MS m/
z: 352 (M þ H)þ.
The binding affinity of selected compounds to the ER
was determined according to Zimmermann et al. [51] using
a and ERb
recombinant human proteins. Briefly, 0.25 pmol of ER
a or ERb,
respectively, were incubated with [3H]-E2 (10 nM) and test
compound for 1 h at room temperature. The potential inhibitors
were dissolved in DMSO (5% final concentration). Evaluation of
non-specific-binding was performed with diethylstilbestrol
4.6.72. (5-Fluoro-3-hydroxyphenyl)-[6-(4-hydroxy-3-
methylphenyl)-pyridin-2-yl]-methanone (24)
The title compound was prepared by reaction of (5-fluoro-3-
methoxyphenyl)-[6-(4-methoxy-3-methylphenyl)-pyridin-2-yl]-
methanone 24a (39 mg, 0.11 mmol, 1 equiv) with pyridinium
hydrochloride (11 mmol, 100 equiv) according to method G. The
product was purified by column chromatography (hexane/ethyl
acetate 6:4) to give 10 mg (28%) of the analytically pure compound
as a yellow solid. C19H14FNO3; MW 323; 1H NMR (acetone-d6):
(10 mM). After incubation, ligandereceptor complexes were selec-
tively bound to hydroxyapatite (5 g/60 mL TE-buffer). The formed
complex was separated, washed and resuspended in ethanol. For
radiodetection, scintillator cocktail (Quickszint 212, Zinsser
Analytic, Frankfurt) was added and samples were measured in
a liquid scintillation counter (Rack Beta Primo 1209, Wallac, Turku).
From these results the percentage of [3H]-E2 displacement by the
compounds was calculated. The plot of % displacement versus
d
9.14 (s, br, 1H), 8.58 (s, br, 1H), 7.86 (dd, J ¼ 1.3 Hz, J ¼ 8.2 Hz, 1H),
7.84e7.80 (m, 1H), 7.72e7.70 (m, 1H), 7.65 (dd, J ¼ 0.9 Hz, J ¼ 7.3 Hz,

16
M. Wetzel et al. / European Journal of Medicinal Chemistry 47 (2012) 1e17
[16] A. Cavalli, A. Bisi, C. Bertucci, C. Rosini, A. Paluszcak, S. Gobbi, E. Giorgio,
A. Rampa, F. Belluti, L. Piazzi, P. Valenti, R.W. Hartmann, M. Recanatini,
Enantioselective nonsteroidal aromatase inhibitors identified through
a multidisciplinary medicinal chemistry approach, J. Med. Chem. 48 (2005)
7282e7289.
[17] M.P. Leze, M. Le Borgne, P. Pinson, A. Palusczak, M. Duflos, G. Le Baut,
R.W. Hartmann, Synthesis and biological evaluation of 5-[(aryl)(1H-imidazol-
1-yl)methyl]-1H-indoles: potent and selective aromatase inhibitors, Bioorg.
Med. Chem. Lett. 16 (2006) 1134e1137.
[18] S. Gobbi, A. Cavalli, M. Negri, K.E. Schewe, F. Belluti, L. Piazzi, R.W. Hartmann,
M. Recanatini, A. Bisi, Imidazolylmethylbenzophenones as highly potent
aromatase inhibitors, J. Med. Chem. 50 (2007) 3420e3422.
[19] S. Haidar, P.B. Ehmer, S. Barassin, C. Batzl-Hartmann, R.W. Hartmann, Effects
of novel 17alpha-hydroxylase/C17, 20-lyase (P450 17, CYP 17) inhibitors on
androgen biosynthesis in vitro and in vivo, J. Steroid Biochem. Mol. Biol. 84
(2003) 555e562.
compound concentration resulted in sigmoidal binding curves. The
compound concentration to displace 50% of the receptor bound
[3H]-E2 were determined. Unlabeled E2 was used as a reference. For
determination of the relative binding affinity the ratio was calcu-
lated according to the following equation: RBA½%ꢄ ¼ ðIC50ðE2Þ
=IC50ðcompoundÞÞ ꢃ 100 [52]. This results in an RBA value of 100%
for E2. After the assay was established and validated a modification
was made to increase throughput. Compounds were tested at
concentrations of 1000 ꢃ IC50(E2). Compounds with less than 50%
displacement of [3H]-E2 at a concentration of 1000 ꢃ IC50(E2) were
classified as RBA <0.1%.
[20] F. Leroux, T.U. Hutschenreuter, C. Charrière, R. Scopelliti, R.W. Hartmann, N-
(4-biphenylmethyl)imidazoles as potential therapeutics for the treatment of
prostate cancer: metabolic robustness due to fluorine substitution? Helv.
Chim. Acta 86 (2003) 2671e2686.
[21] C. Jagusch, M. Negri, U.E. Hille, Q. Hu, M. Bartels, K. Jahn-Hoffmann,
M.A. Pinto-Bazurco Mendieta, B. Rodenwaldt, U. Müller-Vieira, D. Schmidt,
T. Lauterbach, M. Recanatini, A. Cavalli, R.W. Hartmann, Synthesis, biological
evaluation and molecular modelling studies of methyleneimidazole
substituted biaryls as inhibitors of human 17alpha-hydroxylase-17,20-lyase
(CYP17). Part I: heterocyclic modifications of the core structure, Bioorg.
Med. Chem. 16 (2008) 1992e2010.
Acknowledgments
We are grateful to the Deutsche Forschungsgemeinschaft for
financial support (HA1315/12-1). We thank Victoria Krämer, Jean-
nine Jung, Laura Schrobildgen and Jörg Haupenthal for their help in
performing the enzyme inhibition tests (17
the ER tests.
b-HSD2, 17b-HSD1) and
[22] U.E. Hille, Q. Hu, C. Vock, M. Negri, M. Bartels, U. Müller-Vieira, T. Lauterbach,
R.W. Hartmann, Novel CYP17 inhibitors: synthesis, biological evaluation,
structureeactivity relationships and modelling of methoxy- and hydroxy-
substituted methyleneimidazolyl biphenyls, Eur. J. Med. Chem. 44 (2009)
2765e2775.
[23] E. Baston, R.W. Hartmann, N-substituted 4-(5-indolyl)benzoic acids. Synthesis
and evaluation of steroid 5alpha-reductase type I and II inhibitory activity,
Bioorg. Med. Chem. Lett. 9 (1999) 1601e1606.
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